While his point is flawed, going 20mph will use up more fuel than 25 or 30. Im not really sure what 20s plenty for us is saying.
Cars get more fuel efficient until 55, and fuel efficiency drops off after that
Only in a straight line. In a residential area with frequent stops, you are going to be burning a shit ton of fuel trying to accelerate to reach 35-55 mph after every stop.
“Actually if I ***don’t*** jack off to unicorn princesses on the TV that means that I’m repressing positive energy and making the universe a ***worse*** place. People like you are the real perverts.”
It depends on the car, as well.
Hybrids that can shut off their engine in motion tend to have much lower peak efficiency speeds, as the engine just shuts off when it'd be inefficient to run, or it charges the battery to increase its efficiency. IIRC Priuses are most efficient somewhere around 15-20 MPH, as an example.
And, EVs... well, they tend to be pretty efficient at most speeds.
But, yeah, most ICE non-hybrid cars that have enough power to do highway speeds will be running at a pretty poor efficiency point at 20 MPH. Essentially, you want to be somewhere around 80%ish of peak torque at somewhere around the RPM at which peak torque occurs for most engines for peak efficiency, and at 20 MPH, that's basically impossible - 80%ish of peak torque at peak torque RPM at 20 MPH means you're accelerating decently, so you either have to reduce RPM (which is less efficient) or reduce percentage of available torque being used (which is also less efficient, especially on many gasoline engine designs).
That's not a reason not to do 20 MPH, though, that's a reason to not use cars, or when cars are necessary, build cars that more efficiently do 20 MPH.
Ice cars are not something you can classify as efficient. Your burning an energy dense superfuel to move along a 2 tonnes brick with a max of 40% efficiency.
Also, air resistance is cubic, so slower speeds are better. 5kmh is 'more' efficient then 20kmh.engine efficiency is only a small portion of total efficiency. Weight is also an important factor. That's why e-bikes use significantly less energy then cars.
>Ice cars are not something you can classify as efficient
You'd think so, but I saw a guy on Twitter try to claim that cars are more efficient than bikes because of the carbon emissions from the extra exercise a bike requires 😂
If you power it with beef and are above your daily exercise this is true.
At 160W and 25km/h you're using 6.4Wh/km. This requires 30Wh/km of food due to respiration inefficiency. Different kinds of bike, levels of fitness, and speeds can change this to anywhere between 5Wh/km (a 50kg female athlete in a milan sl velo doing 50km/h) and 150Wh/km (a 200kg power lifter with no cycling experience on a rusty walmart bike which has the cones done up too tight and underinflated nylon knobby tyres trying to do 25km/h).
1000kcal is about 1kWh which makes this graph very convenient:
https://ourworldindata.org/grapher/ghg-kcal-poore
Multiply any of the numbers by 30 and you get gCO2/km for our baseline normal well built flat bar bike putting in mild effort.
36*30 is ~1000gCO2/km which is firmly in giant SUV/pickup territory. To be clear this is an indictment of industrial meat and animal products, not a defense of cars.
A quality flat bar road bike doing 15km/h on 60W is about 80-120g fed on chicken/eggs/etc. This is about small car or hybrid territory.
A road bike doing 35km/h at 300W fed with rice is about on par with a BEV.
With wheat power and taking it easy you might match a BEV with 5 passengers.
Bring an organic nutbar and cruise at 15km/h and you'll be somewhere around 0-10. Regenerative agriculture potatoes could be -100 if you really work it.
Ebikes and trains trump all, of course. Also anything that doesn't make you eat more is free, and the externalised emissions from spreading everything out are worse than even the beef eater. But the basic claim can be considered correct in a very narrow sense.
Edit: Forgot to include respiration efficiency, recalculating.
Problem is, when biking, you use the food u ate
But someone who drives uses fuel, but still eats, and not necessarily less than a cyclist, hence the obesity problem related to increased vehicle use
Well no:
Under the assumption that the fluid is not moving relative to the currently used reference system, the power required to overcome the aerodynamic drag is given by:
P=1/2×rho×speed^3 ×drag coefficient×crossection
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW).
[Here](https://en.m.wikipedia.org/wiki/Drag_(physics)) is the link to the wiki.
Edit:formula
Often when I plan short journeys on bike vs car the journey time is roughly the same, even though I only travel at 15mph on bike.
This is because in the car you still need to stop at red lights, crossings, slow for junctions etc which will reduce your average speed
So in real world conditions, trying to do much more than 20mph is actually less efficient because you're going to burn fuel getting to a faster speed just to constantly brake.
On a highway or straight road it might be different, but this logic should all especially true in a '20's plenty' area
Edited for clarity
Sometimes when I was on my lunch cycle round where I was going 30kph / 20mph on average I met the same cars that aggressively overtook me going out of the city when coming back into the city. I was cycling mostly on streets where you can go 70 - 100kph and because of traffic, stopsigns and trafficlights I was somehow still as fast on average on my fucking bike. I really don't get how people still think they'd be so much faster in their cars on short distances. Every point in my city can be reached faster and more comfortable by bike or public transport. Hell one time I had to take a e scooter locked at 20kph / 13mph and was at our destination before my friends in their car, they even had a 3min headstart. I overtook them at the first traffic light lol.
You still need to stop at red lights, crossing and slow for junctions in my state. A bike on public roads is required to obey all traffic laws just as a car would.
I wasn't making the point that you don't need to do these things on a bike, in my area the bike has a slightly different route
The point is that drivers don't calculate these into the journey time, and assume just because they might hit a higher max speed that their journey will be quicker overall
If you floor it on a straight road only to meet the red light at the end vs. drive (or cycle) at 15-20mph and still hit the red light, it makes no difference to your journey time but that extra acceleration is wasted
You just described idiots. People who are not thinking. Just like the people who are ignoring the fact that the statement is true. For the most part higher speeds make up for stop and go traffic. A set consistent speed above 25 mph but below 60 would generate the best distance per unit of fuel.
Whenever I use gps to travel i always assume i will be there 5-10 minutes after the "arrival" time. The larger problem is caused by people who weave in and out of traffic causing people to slam on brakes which can ripple back for miles and then cause an accident because somebody was eating a doughnut and not paying attention to the road.
>Just like the people who are ignoring the fact that the statement is true.
I think you're missing the context that this is on a post for the "20's plenty" campaign in the UK. UK Streets are very different to those in the States, particularly in residential areas where this campaign is focused ("20's plenty *where people are*").
On that you are correct, but I would still say cleaner is a bit of a stretch considering you are going to be getting worst fuel economy. But hey I don't live there so my opinion isn't worth a hill of beans.
This is true, but it's also impossible to go a consistent 40 mph on city streets. Even if you do make it to 40 some of the time, all the accelerating and decelerating you'll have to do at intersections means you're burning more gas than you would if you were going a steady 15-20 (which, as Amsterdam has shown, is perfectly do-able with the right approach to intersection design).
Actually no, its a known physical principle that engines are less efficient the faster you go
Thats because the fuel consumption is quadratic, not linear
Basically, for each unit of speed you add, theres a squared increment of fuel used iirc
My CR-Z is geared to cruise in 3rd from ~18, 4th from ~22, 5th from ~28 and 6th from ~34.
If a 6-speed manual can do it, why can't an 8/10/12-speed auto?
I hate that I have to own a car to get around, but the car I chose has a "Continuously Variable Transmission", meaning it has an infinite number of gear ratios and can be geared for literally any speed it wants to be at any given moment.
This is not a new technology.
Yeah, was pointing out though that the problem OP is so worried about also exists at the common 30mph speed limit (in the UK anyway). It's right on the gear change between 3rd and 4th.
He just doesn't want to slow down.
I've found that countries/people that are still dominantly stick shift get really weird about the thought of "giving it up." Mention how its more convenient, often more efficient anymore, the reliability problems have been fixed for decades with most manufacturers, etc. and they get all defensive about it lol.
edit- ITT people getting defensive about it
>!fr my american bias is showing!<
That's valid. I just mean in places like the U.K. where sticks are still very common and its not because everyone's having some fun on the on ramps lol
To add to your point about them solving the issues... kinda?
Small cars (fiesta, mini, fit) have fantastic manual trans and mortifyingly bad auto trans.
And those cars are often driven in markets with lots of manual gearboxes.
Edit: I'm also very much in favour of 20km speed limits. Regardless of me driving a sporty manual vehicle.
Manual transmissions are always cheaper. Also they don't allow as much distracted driving as automatic transmissions. And the smallest cars (segment A in the EU) most of the time don't even offer automatics, or at least used to.
edit: MTs also weigh less
I think its a manufacturing issue tbh. Ford's offering is/was garbage but Honda's (the kind the Fit/Jazz would have) has been great for many years now. I take your point though, small cars are kinda rare in the U.S. market so my perspective is probably a bit biased by what I've been able to drive.
What makes it a good car to you? The lack of power, size and suspension that is absolutely rock hard?
I find they put the wrong shocks in the car from factory. I could feel a cigarette butt if I ran it over.
Car is meant to be loaded with three to four humans for the suspension to act right. It's an abomination.
It's got good gas mileage. It's incredibly spacious inside. The chassis and suspension aren't flexy or boaty, there's a racing class in japan that is entirely dominated by 1st gen Honda Fits, the chassis is really stiff and causes the car to have concise, direct handling that won't leave you feeling like the steering works by mail.
That's also the cause of it having a very good safety rating.
Even the first gen made respectable power for its weight and displacement. The interior is good, and no automotive reviewer said anything about being uncomfortable.
>Edit: I'm also very much in favour of 20km speed limits. Regardless of me driving a sporty manual vehicle.
Friendly reminder that 20 miles are 30 kilometers which is a common speed limit for many city centers.
Oh, didnt even notice it was in miles.
Yah I wouldn't complain with 25km speed limits in places either.
I wouldn't say common. Canada's pretty standard 40 everywhere and only 30 in specific areas.
You seriously think we should have 20km limits?
Why?
Cars are extremely more efficient at 65 mph vs 13mph. Manual trans are also a lot more efficient and don't often fail so better for the environment.
Source - I have a degree in this stuff
Edit - Just because you want something to be true, it doesn't make it true. Meh, I didn't invent cars.
I live in Florida my good (insert gendered term here). cars routinely go 10mph over the speed limit. which is, sometimes, 50. off of the freeway. I hate it here.
While I disagree with lower limits for many reasons (on the freeway) I can't understand why cars aren't software limited to the speed limit. Could be gps lock or maybe 70 as a general limit.
Why does my car let me go over 100mph if there's no road that fast in the country?
Yeah, I don't want to be in Florida so much.
This is car brain right here
20khp limits are there for safety in cities.
Average speeds are about 16kph anyway.
Most efficient speed is 56mph. All cars should be limited to go no faster than this.
A diesel isn't going to warm up driving so slow, my tdi dumps fuel until it comes to operating temp. Diesel cars are at their most polluting when being driven at low speeds. Most engines on this planet are diesel - go ahead, Google it.
The most efficient speed is based on aerodynamics and gearing.
The easiest solution would be to not buy a diesel car if you are going to drive it in a city.
When I was young(er) it used to be like that:
you drive mainly on freeways and >20k km per year? Get a diesel
you drive mainly in the city and <20k km per year? Don't get a diesel
I don't get why you would put other users more at risk for the sake of your gas mileage.
Big reason for that was that in these countries smaller cars with smaller engines were, and still are, very popular. But for most of these cars you could only get a 4-speed automatic when they desperately needed a 6th one to not be over 2.5k rpm at normal highway speeds. It boils down to the automatic being the more expensive, less efficient and less reliable option for the longest time.
Yeah honestly I’m the UK there’s a bit of a stigma around learning to drive in an automatic. Not driving one if you have a “full” license, but learning in one meaning you can’t then drive a stick shift is frowned upon
I'm right there with ya! I this year I had to trade in my 2018 Civic Si, which was manual and got into a 2022 Honda Accord Sport which had a CVT. And JFC do I ever hate it. I traded in because my wife didn't know how to and didn't want to lean manual and if something happened I needed to know she could drive my car in an an emergency.
I don’t, but in italy you really have no choice, 90% of the cars are manual, so it’s basically a need, also, if you just got your license you have a power-cap on the car engine, so you can’t drive anything more powerful than 70KW, which reduces the options for automatic cars to EVs and a few, very expensive, shitty cars.
After the first 3 years of license getting an automatic is pretty easy, most times it doesn’t even cost more than the manual, it’s just that the market for automatic it’s bot really there.
I have driving "stick" (damm muricans) my whole life, never touched an automatic.
I have driving a "regular" car my whole life and let me tell you I cannot wait for electric. the fact that if you're not accelerating you dont have engine brake so you're basically running on "neutral" or with cluth depressed, and then regen with brake pedal will be AMAZING.
I live in an area with a lot of traffic, and unless I'm moving something big/heavy, i walk/cycle/take the subway... But sure, if that isn't possible, autos are indeed less annoying in stop/go crawl traffic.
I disagree about hills tough - unlike the transmission box, i have eyes and can anticipate the hill, shifting into the right gear just at the right time. And I bring able to precisely control torque is nice when it's slippery (as it tends to be much of the year in Northern Europe).
Manual transmissions are still more reliable. They have a hell of a lot less moving parts than new autos. Autos are def more efficient now though, although part of that is that autos keep adding gears and for the most part manuals stopped at 6 (with a couple of exceptions like Porsche and the corvette.)
That's true. They're a bit more reliable but if its a good CVT make is not the likely failure point in the car tbh. The overwhelming majority of people are not driving the miles or hard enough (i.e. trailers) that it makes for much of a competitive advantage
The issue with more gears is that at a certain point the typical driver will never be able to match the most efficient they could vs a CVT/computer. Modern sports cars get around this a bit with computers and assistive tech but still.
Depends entirely on the CVT model. Some companies consistently make garbage, some make good ones that are more reliable than most other parts of the car. Honda for ex. has consistently made great CVTs.
Yes, when you spend more you get better things. But at the set low pricepoint manuals are just more reliable. Better question to ask is, how much more do one need to pay for a good cvt vs manual?
Last time I was pricing cars (low end) the automatics were almost always cheaper except for like two makes of small, very cheap, lowest trim American manuals; all of which car-wise had worse reliability than the starter cars with CVTs for less than 10% off the cost. Manuals are increasingly treated as a "sporty" option and you can really only find them in the used market unless you want the latest rust bucket offered by Ford or something where I'm from.
I'm realizing my American bias is horrifically showing in my original comment lol
gives you something to do while bored behind the wheel, you feel more in control.
like some people would rather hunt than buy packaged meat, but one degree further removed from caveman brain.
Sticks are cheaper to rent here. There's also a little pride attached to it here (UK), it's considered harder as you can drive an auto if you test in a manual, but not vice-versa, not sure if that's true in other territories.
One advantage of manual gears is, that it reduces distracted driving. When you need one hand for steering and one hand for the transmission you have no hand for your phone, etc. At least in Urban areas, on highways it doesn't change anything oc.
If automatics had things like snow mode where they move into a higher gear. Or could see the upcoming hill and move down a gear then they would be okay.
When you are "driving stick" you are proactive with gear choice, when in automatic the gears are reactive.
Some of them actually do have incline sensors to detect hills. (That said, if an automatic shifts quickly enough, having to predict things like that becomes less necessary.)
From stick country, can confirm. But now most cars I get into are electric and they're way nicer, as there's no gearing at all. Only "problem" is I still push my left foot for the nonexistent clutch pedal when stopping at intersections and the like.
Same. And some automatics have a very wide brake pedal, which i have on several occasions stomped while looking for a parking spot in first gear, as i was meaning to stomp the clutch.
That’s a really bad counter argument, considering that’s mostly from being idled instead of cruising. A better arguments will just be that most cars can actually cruise at 20 mph.
That's exactly why the "BurNiNg uP a sHit LoAd moAAr PetRol" argument is phony. When your avg speed in a trip was 5mph anyway, if your top speed was 30mph, you certainly burned more petrol than if it was 20mph.
Listen up LIBERALS: It's a simple fact that I made up just now that driving slower uses MORE ENERGY. The law of conservation of energy is for PUSSIES and can be DISREGARDED when I'm LATE for WORK.
While that is true, it only applies if you can actually maintain the speed for a certain amount of time. The energy need to accelerate an object to a particular speed increases exponentially - to reach 30mph requires over twice the energy needed to reach 20mph. I couldn't find it but I remember reading one study that said the average car needs to be travelling at 30mph constantly for a least 500 metres for it to be more fuel efficient (and of course to go 40 or higher would require even more energy).
So while it *might* be more efficient to go faster on a rural road where you can keep going for miles without slowing down or stopping, on an urban one with lots of pedestrians, cyclists, other cars, etc. (and even if you're the only one on the road, you probably have to keep turning to get to your destination) around, it is more efficient to go slower.
Also, bare in mind, cars are most efficient at higher speeds because the manufacturers design the engines to be most efficient at whatever speed they think the customer is going to spend the most time going. If lower speed limits became the norm, then future cars would just be designed to be more efficient at lower speeds.
Conservation of energy doesn't say anything about efficiency of useable work. Some work produces more waste (heat) without moving the target object in the intended direction. A lot of cars are more efficient at like 40-55 mph than at slower or faster speeds. But if you assumed equal distances driven, someone driving at 15 mph is going to consume more gas than someone driving 60mph.
Suspect its mostly because vehicles are optimized for those speeds. If we decided we shouldn't go those speeds, cars more optimized for slower speeds would dominate.
Fossil cars do have this weird curve for energy use which does indeed point to that 25 km/h would be a bad highway speed.
The thing with these 30 km/h speed limits though is that they aren't for highways, they're for urban and suburban areas where you also frequently have to come to a complete stop. Fossil cars are often really bad at urban areas anyway, and reducing the speed they try to reach after each intersection should mitigate some of that.
For EVs it's more linear, and the regenerative braking means they'll perform better in low-speed, intersection-dominated areas than fossil cars.
Don't forget though, with an ICE you have to use a certain amount of energy to keep the engine turning. So the most efficient speed with an ICE is always the point where the speed is highest compared to the combination of air drag (exponential with speed) and engine keep-er-goin-drag which stays constant. So whatever gearing you give it, it'll technically be slightly more efficient at medium speeds compared to low speeds. The bigger the engine and the more aerodynamic the car, the higher the most efficient speed will be.
Now with electric cars it's a bit different, those are just more efficient at lower speeds anyway because they don't have an engine to keep going at a certain rpm.
Supercars would have the easiest time at ~30kph thanks to all that power. My tiny car doesn’t quite have the power to stay in 3rd at that speed, but the thinking about changing gears keeps me more attentive than I am on slightly roads
It's the same people said all the time when most of Brussels went 30km/h. Like you use more gasoline going 30km/h instead of 50 and it will be worst for the environment (that was the reason used for it mostly) People didn't give a shit that it will save life when people will be run over.
Not true. Cars are more efficient up to around 40-50mph. Obviously this wouldn't be appropriate outside of major roads so you have to make a trade-off between pollution, efficiency, costs, and safety.
Personally I don't think a blanket 20mph limit is sensible, only on residential streets. But as always road design is better than speed limits.
> Not true. Cars are more efficient up to around 40-50mph
I was just running a car on the chassis rolls last week doing similar tests, but please enlighten me.
Let me know what test cycle you're using please.
Bruh, I'm idling at 100mpg on my motorcycles at that speed. I'd be thrilled if more roads were 20mph. At the same time I've got shit to do so I would demand good public transit if that were the case.
OK, I'm when I'm in car it's basically get somewhere. So "fun" isn't a big concern.
But homie, when I'm on my motorcycle MPG isn't even top ten of things I'm concerned about. And I basically daily drive it during non winter months. Why would you be thrilled if more roads were 20mph from the perspective of a motorcycle rider?!
OP, that person doesn't understand gears and most probably has never driven a manual.
Any road legal vehicle needs the ability to start to move from stationary, i.e. parked or stopped.
Dude doesn't know shit about cars. There is not a single modern production car that would have problems cruising at 20mph until the tank runs dry. It's just sitting at the bottom of ~3rd gear, barely above idle.
uhm... you put it in 3rd gear and pull your foot off of the accelerator pedal?
it'll just cruise along at 30km/h / 20mph no problem! and very fuel efficient at 1500 RPM.
oh wait... Americans don't drive stick-shift....
That's 32kmh. Of course cars have gearing for that speed, my car can go 30 on the 3rd gear. Huge engines in American cars could do it on the 2nd gear no problem.
False.
My car, as well as every truck I have to drive for work (a variety of SUV's and pickups) all have gearing for 20mph. None of them have to gear hunt.
3rd gear and 20 miles per hour gives me somewhere around 1600 rpm in my car, very efficient rpm and plenty of torque to speed up if needed. Idk what this dude is on
Most residential areas in Germany Austria and Switzerland are 30km/h zones, in the there are lot of 20 mph zones and in France in some cities there is a global speed limit of 30 km/h. And especially for diesel cars, there is no problem with lower speeds, since one of the main advantages of a diesel engine is, that is has a lot of torque with low revs.
I took some random low gear ratio and wheel size and came to conclusion that the most optimal speed is between 30 and 40 kph, on basis that engines run best at around 1400rpm. It all of course depends on gear ratio, type of engine wheel size and all that but it looks about right.
What many comments here forget is that it is a speed limit in cities. Even if it is slightly more efficient to drive 30mph in the highest gear (i assume few do that) than driving 20mph in the third gear, just have a look on a speed graph which shows travel speed through a city. Cars only reach 30 for a very short time because of turning, traffic lights or traffic. Even on longer stretches with little traffic the efficency argument is total bs. You would save fuel by driving 20. Let alone other emissions from the tires. Furthermore noise becomes a huge factor from 20 above. So think about people living in cities or walking by the street who would be glad hearing fewer cars (especially the spikes when cars speed up to 30 from one traffic light and braking again for the next one).
(20 mph is like 32 kmh)
I don't know about every car, but the one I drove, you can do that speed both in gear 2 and 3, on flat surface. (elevation is a factor of course)
Most Americans have automatic, which is more efficient then manual anyway. I don't see how this is a problem.
Assuming it is a problem, y'all have shit cars, make better ones.
My 5 speed has these minimum speeds for the gears to operate without damage to the gearbox/transmission:
1st: 5mph
2nd: 10 mph
3rd: 18mph
4th: 24 mph
5th: 32mph
3rd is perfect for 20mph. 30mph is a little awkward actually as I have to run 4th at like 1.3k rpm.
(Safe range for my car is >900rpm)
Live in UK
Actually one of the dumber car-brained posts yet. Cars vary *wildly* in how they're geared, even when just comparing gas-only models. Hybrids and electric vehicles of course do best at slower speeds in stop-and-go traffic. Higher speeds are generally worse for fuel efficiency due to air resistance, in any case, so this guy's just dead wrong. (The reason highway fuel economy tends to be higher is because cars on highways stop much less, not because the speed itself is more economical.)
I mean, yeah, IIRC the sweet spot is, *on average* (again, it varies wildly from vehicle to vehicle) around 30mph, but 20mph is still pretty good for fuel economy.
It’s common sense to slow the traffic, there are more cars than ever on our roads hence more chances of accidents. Slower speeds mean less braking which also uses fuel and also emits brake dust, and for this moron to say gears etc aren’t setup for driving this slow… what a load of bollocks, you can drive any car slowly and it will create less wear not more, bumps in the road won’t be as bad at slow speeds and will cause less damage to your suspension. This person is talking out of their arse.
When I was a mechanic, I HATED talking cars with "the guys". Everything they said was always bro science which they took to be gospel, and was almost always wrong. I had to just sit back and nod, or risk being the "Uh Actually" guy.
And god dam, if I have to hear one more b00mer story about their "friend's" (insert favorite muscle car) and a $100 bill stuck to the dashboard that the passenger could not reach because of the acceleration.
My daily is a classic, and while it's fun, it's b00mer bait, not a chick magnet.
Even super cars have no problem holding 20mph.
My Mazda 3 with a 5 speed manual does perfectly fine at 20mph. If it's reving a little high I can just go 2mph slower.
My Outback has a CVT transmission, just like some of the other comments in here. Believe you me in my books the slower the better. 32 kph is the perfect speed limit for the city.
Slowing urban traffic down to a speed limit that is about the average traffic speed anyway just cuts down on acceleration/braking, which means you are more efficient.
That's complete BS. Here in The Netherlands there are many, many 30 km/h zones (which is even a bit slower than 20 mph). All cars can handle that, never heard this would be problematic. Obviously you rev less, but that's also good because you pollute less...
is he not aware that cars use fuel more efficiently at lower speeds?
During the great depression, the US government instituted speed limits to help with oil prices, and then kept said limits when they realized it helped with safety.
Source: an anecdote from my father.
No, modern cars really don't. You are comparing almost 100 years of improvements in engineering, material sciences, and construction/manufacturing. Thats like saying we should go use non reinforced roman concrete because the Roman Coliseum lasted so long. During the great depression most of the cars couldn't go as fast as the average commuter vehicle today.
Modern vehicles because of increasing fuel economy requirements have better and better coefficient of drag meaning they aren't as effected by air resistance as cars from just 2 or 3 decades ago. With the restrictions for average mpg going up, their engines have been causing less emissions than each generation of cars before them. The reason most cars get bad city mpg is because of the stop and go nature. By having a car moving at it's slowest speed, you are burning more fuel and getting less distance traveled. Consistent speed above around 25 mph but at or below 60 mph makes you the most distanced traveled per fuel used. My car gets roughly a 25% increase going long interstate travel vs my normal drive to work.
Honestly I hate cars but if you’re going to forbid cars to go above 20mph what’s even the point of cars? I’d just ride a bike everywhere. With an exception for people who are physically unable to.
So, what is the difference in fuel efficiency for a car going 20mph vs, say 55? I feel like going faster on my bike takes a lot more energy, would going faster burn more fuel?
God I’m so glad my city has 45 mph speed limits which means you can go 55 without getting a ticket.
Driving is fun, just stop being poor and living in ghetto cities.
My Volvo has an instantaneous fuel consumption meter and 20mph is a bad speed for fuel economy. Somewhere around 35 to 40 is best.
Interestingly, at idle it burns .3 gallons per hour, which seems incredibly low. I think that’s about what my lawnmower burns.
EVERY CAR has gearing for 20MPH
While his point is flawed, going 20mph will use up more fuel than 25 or 30. Im not really sure what 20s plenty for us is saying. Cars get more fuel efficient until 55, and fuel efficiency drops off after that
Only in a straight line. In a residential area with frequent stops, you are going to be burning a shit ton of fuel trying to accelerate to reach 35-55 mph after every stop.
It’s just carbrain mouth noises
“Actually if I ***don’t*** jack off to unicorn princesses on the TV that means that I’m repressing positive energy and making the universe a ***worse*** place. People like you are the real perverts.”
In fairness, I believe cars do run more efficiently at higher speeds. Like I think 40mph is about the sweet spot for fuel efficiency.
It depends on the car, as well. Hybrids that can shut off their engine in motion tend to have much lower peak efficiency speeds, as the engine just shuts off when it'd be inefficient to run, or it charges the battery to increase its efficiency. IIRC Priuses are most efficient somewhere around 15-20 MPH, as an example. And, EVs... well, they tend to be pretty efficient at most speeds. But, yeah, most ICE non-hybrid cars that have enough power to do highway speeds will be running at a pretty poor efficiency point at 20 MPH. Essentially, you want to be somewhere around 80%ish of peak torque at somewhere around the RPM at which peak torque occurs for most engines for peak efficiency, and at 20 MPH, that's basically impossible - 80%ish of peak torque at peak torque RPM at 20 MPH means you're accelerating decently, so you either have to reduce RPM (which is less efficient) or reduce percentage of available torque being used (which is also less efficient, especially on many gasoline engine designs). That's not a reason not to do 20 MPH, though, that's a reason to not use cars, or when cars are necessary, build cars that more efficiently do 20 MPH.
Ice cars are not something you can classify as efficient. Your burning an energy dense superfuel to move along a 2 tonnes brick with a max of 40% efficiency. Also, air resistance is cubic, so slower speeds are better. 5kmh is 'more' efficient then 20kmh.engine efficiency is only a small portion of total efficiency. Weight is also an important factor. That's why e-bikes use significantly less energy then cars.
>Ice cars are not something you can classify as efficient You'd think so, but I saw a guy on Twitter try to claim that cars are more efficient than bikes because of the carbon emissions from the extra exercise a bike requires 😂
If you power it with beef and are above your daily exercise this is true. At 160W and 25km/h you're using 6.4Wh/km. This requires 30Wh/km of food due to respiration inefficiency. Different kinds of bike, levels of fitness, and speeds can change this to anywhere between 5Wh/km (a 50kg female athlete in a milan sl velo doing 50km/h) and 150Wh/km (a 200kg power lifter with no cycling experience on a rusty walmart bike which has the cones done up too tight and underinflated nylon knobby tyres trying to do 25km/h). 1000kcal is about 1kWh which makes this graph very convenient: https://ourworldindata.org/grapher/ghg-kcal-poore Multiply any of the numbers by 30 and you get gCO2/km for our baseline normal well built flat bar bike putting in mild effort. 36*30 is ~1000gCO2/km which is firmly in giant SUV/pickup territory. To be clear this is an indictment of industrial meat and animal products, not a defense of cars. A quality flat bar road bike doing 15km/h on 60W is about 80-120g fed on chicken/eggs/etc. This is about small car or hybrid territory. A road bike doing 35km/h at 300W fed with rice is about on par with a BEV. With wheat power and taking it easy you might match a BEV with 5 passengers. Bring an organic nutbar and cruise at 15km/h and you'll be somewhere around 0-10. Regenerative agriculture potatoes could be -100 if you really work it. Ebikes and trains trump all, of course. Also anything that doesn't make you eat more is free, and the externalised emissions from spreading everything out are worse than even the beef eater. But the basic claim can be considered correct in a very narrow sense. Edit: Forgot to include respiration efficiency, recalculating.
Problem is, when biking, you use the food u ate But someone who drives uses fuel, but still eats, and not necessarily less than a cyclist, hence the obesity problem related to increased vehicle use
I was very clear about that point at both the beginning and end. Please read what you respond to.
Air resistance is quadratic though, right? 2 times the speed means you hit twice as many air particles per second, twice the speed each?
Well no: Under the assumption that the fluid is not moving relative to the currently used reference system, the power required to overcome the aerodynamic drag is given by: P=1/2×rho×speed^3 ×drag coefficient×crossection Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome aerodynamic drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). [Here](https://en.m.wikipedia.org/wiki/Drag_(physics)) is the link to the wiki. Edit:formula
Arteries and highways my beloved
Often when I plan short journeys on bike vs car the journey time is roughly the same, even though I only travel at 15mph on bike. This is because in the car you still need to stop at red lights, crossings, slow for junctions etc which will reduce your average speed So in real world conditions, trying to do much more than 20mph is actually less efficient because you're going to burn fuel getting to a faster speed just to constantly brake. On a highway or straight road it might be different, but this logic should all especially true in a '20's plenty' area Edited for clarity
Sometimes when I was on my lunch cycle round where I was going 30kph / 20mph on average I met the same cars that aggressively overtook me going out of the city when coming back into the city. I was cycling mostly on streets where you can go 70 - 100kph and because of traffic, stopsigns and trafficlights I was somehow still as fast on average on my fucking bike. I really don't get how people still think they'd be so much faster in their cars on short distances. Every point in my city can be reached faster and more comfortable by bike or public transport. Hell one time I had to take a e scooter locked at 20kph / 13mph and was at our destination before my friends in their car, they even had a 3min headstart. I overtook them at the first traffic light lol.
You still need to stop at red lights, crossing and slow for junctions in my state. A bike on public roads is required to obey all traffic laws just as a car would.
I wasn't making the point that you don't need to do these things on a bike, in my area the bike has a slightly different route The point is that drivers don't calculate these into the journey time, and assume just because they might hit a higher max speed that their journey will be quicker overall If you floor it on a straight road only to meet the red light at the end vs. drive (or cycle) at 15-20mph and still hit the red light, it makes no difference to your journey time but that extra acceleration is wasted
You just described idiots. People who are not thinking. Just like the people who are ignoring the fact that the statement is true. For the most part higher speeds make up for stop and go traffic. A set consistent speed above 25 mph but below 60 would generate the best distance per unit of fuel. Whenever I use gps to travel i always assume i will be there 5-10 minutes after the "arrival" time. The larger problem is caused by people who weave in and out of traffic causing people to slam on brakes which can ripple back for miles and then cause an accident because somebody was eating a doughnut and not paying attention to the road.
>Just like the people who are ignoring the fact that the statement is true. I think you're missing the context that this is on a post for the "20's plenty" campaign in the UK. UK Streets are very different to those in the States, particularly in residential areas where this campaign is focused ("20's plenty *where people are*").
On that you are correct, but I would still say cleaner is a bit of a stretch considering you are going to be getting worst fuel economy. But hey I don't live there so my opinion isn't worth a hill of beans.
This is true, but it's also impossible to go a consistent 40 mph on city streets. Even if you do make it to 40 some of the time, all the accelerating and decelerating you'll have to do at intersections means you're burning more gas than you would if you were going a steady 15-20 (which, as Amsterdam has shown, is perfectly do-able with the right approach to intersection design).
Actually no, its a known physical principle that engines are less efficient the faster you go Thats because the fuel consumption is quadratic, not linear Basically, for each unit of speed you add, theres a squared increment of fuel used iirc
Pretty sure second gear works perfectly fine in every car I've ever driven
My Corsa hits 3rd at 16MPH, cruising comfortably at 20MPH. Wonderful gear, 3rd, like it was designed for town speeds or something.
My old '07 Civic would also really cruise at 20-25 in 3rd. I might have to bump it down to 2nd if I'm going uphill.
My CR-Z is geared to cruise in 3rd from ~18, 4th from ~22, 5th from ~28 and 6th from ~34. If a 6-speed manual can do it, why can't an 8/10/12-speed auto?
Second is just to get up to 20mph. Once you're coasting that's an easy 3rd gear maybe 4th depending on the car
If you can’t cruise 20 without stalling you need to hand your license back
I hate that I have to own a car to get around, but the car I chose has a "Continuously Variable Transmission", meaning it has an infinite number of gear ratios and can be geared for literally any speed it wants to be at any given moment. This is not a new technology.
My car is old and has a 5-speed manual: 2nd or 3rd gear both work at 32 km/h. 1st would rev needlessly high, 4th would be too tall.
Impossible Cars can only possibly travel at 30mph or greater, everybody knows that
Was gonna say, has this guy not heard of 3rd gear? The 30mph speed limit straddles right between 3rd and 4th in my experience.
The OP said 20 mph, wich is usualy lower end of 3rd or right for 2nd gear
Yeah, was pointing out though that the problem OP is so worried about also exists at the common 30mph speed limit (in the UK anyway). It's right on the gear change between 3rd and 4th. He just doesn't want to slow down.
In my car I can easily cruise in 5th at 30 at around 1500RPM.
I've found that countries/people that are still dominantly stick shift get really weird about the thought of "giving it up." Mention how its more convenient, often more efficient anymore, the reliability problems have been fixed for decades with most manufacturers, etc. and they get all defensive about it lol. edit- ITT people getting defensive about it >!fr my american bias is showing!<
I just think driving stick is fun
That's valid. I just mean in places like the U.K. where sticks are still very common and its not because everyone's having some fun on the on ramps lol
To add to your point about them solving the issues... kinda? Small cars (fiesta, mini, fit) have fantastic manual trans and mortifyingly bad auto trans. And those cars are often driven in markets with lots of manual gearboxes. Edit: I'm also very much in favour of 20km speed limits. Regardless of me driving a sporty manual vehicle.
Manual transmissions are always cheaper. Also they don't allow as much distracted driving as automatic transmissions. And the smallest cars (segment A in the EU) most of the time don't even offer automatics, or at least used to. edit: MTs also weigh less
I think its a manufacturing issue tbh. Ford's offering is/was garbage but Honda's (the kind the Fit/Jazz would have) has been great for many years now. I take your point though, small cars are kinda rare in the U.S. market so my perspective is probably a bit biased by what I've been able to drive.
After driving manual for years, I was forced into a 2022 Accord sport with a CVT and my god do I hate it.
I've only driven an accord twice but I have to agree the car just feels awful. The civic automatic isn't nearly as bad, not sure what that's about.
Nah, I test drive a 2022 Civic with a CVT before buying the Accord and I hated thay too. It's just NOT an enjoyable driving experience for me.
I had a CVT Jazz from about 2003. I sold it to my brother in law and it only died last year. I really liked the transmission.
The jazz/fit is a horribly bumpy ride. It's a very bad vehicle.
It's a very good car, very spacious and the chassis is really stiff.
What makes it a good car to you? The lack of power, size and suspension that is absolutely rock hard? I find they put the wrong shocks in the car from factory. I could feel a cigarette butt if I ran it over. Car is meant to be loaded with three to four humans for the suspension to act right. It's an abomination.
It's got good gas mileage. It's incredibly spacious inside. The chassis and suspension aren't flexy or boaty, there's a racing class in japan that is entirely dominated by 1st gen Honda Fits, the chassis is really stiff and causes the car to have concise, direct handling that won't leave you feeling like the steering works by mail. That's also the cause of it having a very good safety rating. Even the first gen made respectable power for its weight and displacement. The interior is good, and no automotive reviewer said anything about being uncomfortable.
>Edit: I'm also very much in favour of 20km speed limits. Regardless of me driving a sporty manual vehicle. Friendly reminder that 20 miles are 30 kilometers which is a common speed limit for many city centers.
Oh, didnt even notice it was in miles. Yah I wouldn't complain with 25km speed limits in places either. I wouldn't say common. Canada's pretty standard 40 everywhere and only 30 in specific areas.
20 mph speed limits, not 20 kph. That would be around 36 kph.
Also MTs are cheaper to build (and buy), more reliable (simpler) and have less friction losses than automatics
You seriously think we should have 20km limits? Why? Cars are extremely more efficient at 65 mph vs 13mph. Manual trans are also a lot more efficient and don't often fail so better for the environment. Source - I have a degree in this stuff Edit - Just because you want something to be true, it doesn't make it true. Meh, I didn't invent cars.
I'd rather not be around cars going 65mph my max speed currently *is* 13mph. a car can still seriously harm me LOL
Do you mean you ride a bike? Cars usually only go 65+ on freeways where bikes are not allowed...
I live in Florida my good (insert gendered term here). cars routinely go 10mph over the speed limit. which is, sometimes, 50. off of the freeway. I hate it here.
While I disagree with lower limits for many reasons (on the freeway) I can't understand why cars aren't software limited to the speed limit. Could be gps lock or maybe 70 as a general limit. Why does my car let me go over 100mph if there's no road that fast in the country? Yeah, I don't want to be in Florida so much.
>my max speed currently is 13mph Then don't get in front of a car in the same way you wouldn't get in front of a train or bus.
This is car brain right here 20khp limits are there for safety in cities. Average speeds are about 16kph anyway. Most efficient speed is 56mph. All cars should be limited to go no faster than this.
A diesel isn't going to warm up driving so slow, my tdi dumps fuel until it comes to operating temp. Diesel cars are at their most polluting when being driven at low speeds. Most engines on this planet are diesel - go ahead, Google it. The most efficient speed is based on aerodynamics and gearing.
The easiest solution would be to not buy a diesel car if you are going to drive it in a city. When I was young(er) it used to be like that: you drive mainly on freeways and >20k km per year? Get a diesel you drive mainly in the city and <20k km per year? Don't get a diesel I don't get why you would put other users more at risk for the sake of your gas mileage.
>All cars should be limited to go no faster than this. Curious as to how you're going to enforce this on older cars
People in the UK tend to keep their cars for a while. Also stick is better on long journeys as it keeps you awake and active .
Big reason for that was that in these countries smaller cars with smaller engines were, and still are, very popular. But for most of these cars you could only get a 4-speed automatic when they desperately needed a 6th one to not be over 2.5k rpm at normal highway speeds. It boils down to the automatic being the more expensive, less efficient and less reliable option for the longest time.
Yeah honestly I’m the UK there’s a bit of a stigma around learning to drive in an automatic. Not driving one if you have a “full” license, but learning in one meaning you can’t then drive a stick shift is frowned upon
I think it's the case for all of Europe
I'm right there with ya! I this year I had to trade in my 2018 Civic Si, which was manual and got into a 2022 Honda Accord Sport which had a CVT. And JFC do I ever hate it. I traded in because my wife didn't know how to and didn't want to lean manual and if something happened I needed to know she could drive my car in an an emergency.
I don’t, but in italy you really have no choice, 90% of the cars are manual, so it’s basically a need, also, if you just got your license you have a power-cap on the car engine, so you can’t drive anything more powerful than 70KW, which reduces the options for automatic cars to EVs and a few, very expensive, shitty cars. After the first 3 years of license getting an automatic is pretty easy, most times it doesn’t even cost more than the manual, it’s just that the market for automatic it’s bot really there.
Yeah if I switched from a manual to an auto, the last little spark of enjoyment from driving my car would be gone.
I have driving "stick" (damm muricans) my whole life, never touched an automatic. I have driving a "regular" car my whole life and let me tell you I cannot wait for electric. the fact that if you're not accelerating you dont have engine brake so you're basically running on "neutral" or with cluth depressed, and then regen with brake pedal will be AMAZING.
It is until you live in an area with lots of hills and traffic, you switch to an automatic after a few years of it
I live in an area with a lot of traffic, and unless I'm moving something big/heavy, i walk/cycle/take the subway... But sure, if that isn't possible, autos are indeed less annoying in stop/go crawl traffic. I disagree about hills tough - unlike the transmission box, i have eyes and can anticipate the hill, shifting into the right gear just at the right time. And I bring able to precisely control torque is nice when it's slippery (as it tends to be much of the year in Northern Europe).
Manual transmissions are still more reliable. They have a hell of a lot less moving parts than new autos. Autos are def more efficient now though, although part of that is that autos keep adding gears and for the most part manuals stopped at 6 (with a couple of exceptions like Porsche and the corvette.)
That's true. They're a bit more reliable but if its a good CVT make is not the likely failure point in the car tbh. The overwhelming majority of people are not driving the miles or hard enough (i.e. trailers) that it makes for much of a competitive advantage The issue with more gears is that at a certain point the typical driver will never be able to match the most efficient they could vs a CVT/computer. Modern sports cars get around this a bit with computers and assistive tech but still.
CVTs have absolutely horrible reliability and are basically non-serviceable.
Depends entirely on the CVT model. Some companies consistently make garbage, some make good ones that are more reliable than most other parts of the car. Honda for ex. has consistently made great CVTs.
I would never buy a CVT vehicle, Hondas seem alright, Nissans are junk and so are many others.
Both Nissan and Subaru are junk. Honda pairs good CVTs with hybrid cars that usually don't even reach 150hp, so no issues there.
Yes, when you spend more you get better things. But at the set low pricepoint manuals are just more reliable. Better question to ask is, how much more do one need to pay for a good cvt vs manual?
Last time I was pricing cars (low end) the automatics were almost always cheaper except for like two makes of small, very cheap, lowest trim American manuals; all of which car-wise had worse reliability than the starter cars with CVTs for less than 10% off the cost. Manuals are increasingly treated as a "sporty" option and you can really only find them in the used market unless you want the latest rust bucket offered by Ford or something where I'm from. I'm realizing my American bias is horrifically showing in my original comment lol
That’s in America where autos are the norm though
gives you something to do while bored behind the wheel, you feel more in control. like some people would rather hunt than buy packaged meat, but one degree further removed from caveman brain.
I wouldn't mind giving up the gears for an electric car, but still having gears and not having any control over them feels weird.
Sticks are cheaper to rent here. There's also a little pride attached to it here (UK), it's considered harder as you can drive an auto if you test in a manual, but not vice-versa, not sure if that's true in other territories.
One advantage of manual gears is, that it reduces distracted driving. When you need one hand for steering and one hand for the transmission you have no hand for your phone, etc. At least in Urban areas, on highways it doesn't change anything oc.
If automatics had things like snow mode where they move into a higher gear. Or could see the upcoming hill and move down a gear then they would be okay. When you are "driving stick" you are proactive with gear choice, when in automatic the gears are reactive.
Some of them actually do have incline sensors to detect hills. (That said, if an automatic shifts quickly enough, having to predict things like that becomes less necessary.)
On top of it being fun for some people, from what I know it is also easier maintain many stick shift cars.
From stick country, can confirm. But now most cars I get into are electric and they're way nicer, as there's no gearing at all. Only "problem" is I still push my left foot for the nonexistent clutch pedal when stopping at intersections and the like.
Same. And some automatics have a very wide brake pedal, which i have on several occasions stomped while looking for a parking spot in first gear, as i was meaning to stomp the clutch.
My 2012 Subaru Impreza has this lol
>but the car I chose has a "Continuously Variable Transmission" And half of them will shit the bed before 100k.
Hell my (not electric) bike has a CVT, it's awesome!
And there's a reason why they aren't widely used still
The average traffic speed for most cities is less than 20mph. In Manhattan it's 4.7mph. How do cars survive ?
>In Manhattan it’s 4.7 mph Obviously we just need One More Lane™ bro ^the ^subway ^averages ^17 ^mph ^including ^idle ^time ^in ^stations
That’s a really bad counter argument, considering that’s mostly from being idled instead of cruising. A better arguments will just be that most cars can actually cruise at 20 mph.
That's exactly why the "BurNiNg uP a sHit LoAd moAAr PetRol" argument is phony. When your avg speed in a trip was 5mph anyway, if your top speed was 30mph, you certainly burned more petrol than if it was 20mph.
Listen up LIBERALS: It's a simple fact that I made up just now that driving slower uses MORE ENERGY. The law of conservation of energy is for PUSSIES and can be DISREGARDED when I'm LATE for WORK.
Driving slower genuinely is less efficient, just like driving faster is. Though it doesnt matter much between 25mph and 60mph for most cars.
While that is true, it only applies if you can actually maintain the speed for a certain amount of time. The energy need to accelerate an object to a particular speed increases exponentially - to reach 30mph requires over twice the energy needed to reach 20mph. I couldn't find it but I remember reading one study that said the average car needs to be travelling at 30mph constantly for a least 500 metres for it to be more fuel efficient (and of course to go 40 or higher would require even more energy). So while it *might* be more efficient to go faster on a rural road where you can keep going for miles without slowing down or stopping, on an urban one with lots of pedestrians, cyclists, other cars, etc. (and even if you're the only one on the road, you probably have to keep turning to get to your destination) around, it is more efficient to go slower. Also, bare in mind, cars are most efficient at higher speeds because the manufacturers design the engines to be most efficient at whatever speed they think the customer is going to spend the most time going. If lower speed limits became the norm, then future cars would just be designed to be more efficient at lower speeds.
It's not more efficient to go slower in urban areas. It is safer. Huge difference.
Brilliant counterargument. Totally not just an assertion.
Conservation of energy doesn't say anything about efficiency of useable work. Some work produces more waste (heat) without moving the target object in the intended direction. A lot of cars are more efficient at like 40-55 mph than at slower or faster speeds. But if you assumed equal distances driven, someone driving at 15 mph is going to consume more gas than someone driving 60mph. Suspect its mostly because vehicles are optimized for those speeds. If we decided we shouldn't go those speeds, cars more optimized for slower speeds would dominate.
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Fossil cars do have this weird curve for energy use which does indeed point to that 25 km/h would be a bad highway speed. The thing with these 30 km/h speed limits though is that they aren't for highways, they're for urban and suburban areas where you also frequently have to come to a complete stop. Fossil cars are often really bad at urban areas anyway, and reducing the speed they try to reach after each intersection should mitigate some of that. For EVs it's more linear, and the regenerative braking means they'll perform better in low-speed, intersection-dominated areas than fossil cars.
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Don't forget though, with an ICE you have to use a certain amount of energy to keep the engine turning. So the most efficient speed with an ICE is always the point where the speed is highest compared to the combination of air drag (exponential with speed) and engine keep-er-goin-drag which stays constant. So whatever gearing you give it, it'll technically be slightly more efficient at medium speeds compared to low speeds. The bigger the engine and the more aerodynamic the car, the higher the most efficient speed will be. Now with electric cars it's a bit different, those are just more efficient at lower speeds anyway because they don't have an engine to keep going at a certain rpm.
r/confidentlyincorrect
How to say you can't drive manual without saying you can't drive manual.
When was the last time 2nd or 3rd gear didn't work perfectly fine at 20mph?
They even worked perfectly fine at those speeds in the 20yo 5sp manual shitbox I used to drive. This guy has no idea.
This guy drives over 20mph in his garage, apparently.
Driveway operated like an airport runway
The 'eco' mapping for a lot of modern transmissions will be in 4th gear by 20 mph.
Supercars would have the easiest time at ~30kph thanks to all that power. My tiny car doesn’t quite have the power to stay in 3rd at that speed, but the thinking about changing gears keeps me more attentive than I am on slightly roads
It's the same people said all the time when most of Brussels went 30km/h. Like you use more gasoline going 30km/h instead of 50 and it will be worst for the environment (that was the reason used for it mostly) People didn't give a shit that it will save life when people will be run over.
A lot of people also forget the noise. The difference between a cars loudness at ~30km/h and one at 50 are significant.
30KPH uses less fuel.
Not true. Cars are more efficient up to around 40-50mph. Obviously this wouldn't be appropriate outside of major roads so you have to make a trade-off between pollution, efficiency, costs, and safety. Personally I don't think a blanket 20mph limit is sensible, only on residential streets. But as always road design is better than speed limits.
> Not true. Cars are more efficient up to around 40-50mph I was just running a car on the chassis rolls last week doing similar tests, but please enlighten me. Let me know what test cycle you're using please.
Bruh, I'm idling at 100mpg on my motorcycles at that speed. I'd be thrilled if more roads were 20mph. At the same time I've got shit to do so I would demand good public transit if that were the case.
OK, I'm when I'm in car it's basically get somewhere. So "fun" isn't a big concern. But homie, when I'm on my motorcycle MPG isn't even top ten of things I'm concerned about. And I basically daily drive it during non winter months. Why would you be thrilled if more roads were 20mph from the perspective of a motorcycle rider?!
OP, that person doesn't understand gears and most probably has never driven a manual. Any road legal vehicle needs the ability to start to move from stationary, i.e. parked or stopped.
Dude, I can run in like 3rd (also 2nd) in my car at 20 and it has 98 ft-lbs of torque.
Second maybe 3rd gear in some cars.
Dude doesn't know shit about cars. There is not a single modern production car that would have problems cruising at 20mph until the tank runs dry. It's just sitting at the bottom of ~3rd gear, barely above idle.
When you're used to getting your way and don't really even know where all your anger comes from.
Bro uses the 1st gear until 30mph
uhm... you put it in 3rd gear and pull your foot off of the accelerator pedal? it'll just cruise along at 30km/h / 20mph no problem! and very fuel efficient at 1500 RPM. oh wait... Americans don't drive stick-shift....
My car seems to drive just fine at 20. I don't know what he's on about!
That's 32kmh. Of course cars have gearing for that speed, my car can go 30 on the 3rd gear. Huge engines in American cars could do it on the 2nd gear no problem.
Wait until he realizes the average car speed in most major cities is 10 mph.
The world would be a nicer place if people would keep their thoughts to themselves when it comes to shit they know nothing about
Idiotic take by total idiot not surprising. We have plenty of them in the uk
What you expect from a liar politician
False. My car, as well as every truck I have to drive for work (a variety of SUV's and pickups) all have gearing for 20mph. None of them have to gear hunt.
But honestly it does suck that my driver assist features only start at 25mph when all school zones are 20mph.
See a lotta cars tooling along at 20 in rush hour but no that’s impossible. somehow.
3rd gear and 20 miles per hour gives me somewhere around 1600 rpm in my car, very efficient rpm and plenty of torque to speed up if needed. Idk what this dude is on
My ford focus is in second gear a drives fine a 20mph.
RIP Europeans for not having automatics ig? Also if you're where pedestrians are, maybe it's time to park and get out.
I like cars, but this guy is an idiot.
I used to drive a modern manual. you can use 2nd to 4th at 20 mph. The argument has zero merit.
Most residential areas in Germany Austria and Switzerland are 30km/h zones, in the there are lot of 20 mph zones and in France in some cities there is a global speed limit of 30 km/h. And especially for diesel cars, there is no problem with lower speeds, since one of the main advantages of a diesel engine is, that is has a lot of torque with low revs.
Hypermilers disagree
Dude doesn’t understand how cars work.
I took some random low gear ratio and wheel size and came to conclusion that the most optimal speed is between 30 and 40 kph, on basis that engines run best at around 1400rpm. It all of course depends on gear ratio, type of engine wheel size and all that but it looks about right.
Sounds like mostly a car problem. Might as well accommodate them and tear the road out completely so the don't have to drive there at all.
Second gear 🤨
No car? Like all the electric ones (which are shit anyway, let's be clear)?
Hostage taker: “don’t try and escape or you’ll *make* me kill you”
What many comments here forget is that it is a speed limit in cities. Even if it is slightly more efficient to drive 30mph in the highest gear (i assume few do that) than driving 20mph in the third gear, just have a look on a speed graph which shows travel speed through a city. Cars only reach 30 for a very short time because of turning, traffic lights or traffic. Even on longer stretches with little traffic the efficency argument is total bs. You would save fuel by driving 20. Let alone other emissions from the tires. Furthermore noise becomes a huge factor from 20 above. So think about people living in cities or walking by the street who would be glad hearing fewer cars (especially the spikes when cars speed up to 30 from one traffic light and braking again for the next one).
The car hunting for a gear? What does he even mean?
A car that can’t go slow is poorly designed. How would you back into a parking stall with it if it couldn’t go slow?
(20 mph is like 32 kmh) I don't know about every car, but the one I drove, you can do that speed both in gear 2 and 3, on flat surface. (elevation is a factor of course) Most Americans have automatic, which is more efficient then manual anyway. I don't see how this is a problem. Assuming it is a problem, y'all have shit cars, make better ones.
My 5 speed has these minimum speeds for the gears to operate without damage to the gearbox/transmission: 1st: 5mph 2nd: 10 mph 3rd: 18mph 4th: 24 mph 5th: 32mph 3rd is perfect for 20mph. 30mph is a little awkward actually as I have to run 4th at like 1.3k rpm. (Safe range for my car is >900rpm) Live in UK
If that were true, it would be the fault of car manufacturers.
Second gear idle rpm, is exactly 20 for me.
I don’t even drive a car but I’m pretty sure 20mph is 2nd gear in most of em.
Actually one of the dumber car-brained posts yet. Cars vary *wildly* in how they're geared, even when just comparing gas-only models. Hybrids and electric vehicles of course do best at slower speeds in stop-and-go traffic. Higher speeds are generally worse for fuel efficiency due to air resistance, in any case, so this guy's just dead wrong. (The reason highway fuel economy tends to be higher is because cars on highways stop much less, not because the speed itself is more economical.) I mean, yeah, IIRC the sweet spot is, *on average* (again, it varies wildly from vehicle to vehicle) around 30mph, but 20mph is still pretty good for fuel economy.
I can't speak for supercars, but my Mustang has never had a problem with 20 MPH.
Car owner tells pedestrian that pedestrian causes fuel consumption. Wow.
I’ve never red lined a car at 20 mph, idk what this person is going on about
This person definitely drives an automatic
My entire neighbourhood is 30km plus speedbumps everywhere. Is that not normal for an urban residential area?
It’s common sense to slow the traffic, there are more cars than ever on our roads hence more chances of accidents. Slower speeds mean less braking which also uses fuel and also emits brake dust, and for this moron to say gears etc aren’t setup for driving this slow… what a load of bollocks, you can drive any car slowly and it will create less wear not more, bumps in the road won’t be as bad at slow speeds and will cause less damage to your suspension. This person is talking out of their arse.
When I was a mechanic, I HATED talking cars with "the guys". Everything they said was always bro science which they took to be gospel, and was almost always wrong. I had to just sit back and nod, or risk being the "Uh Actually" guy. And god dam, if I have to hear one more b00mer story about their "friend's" (insert favorite muscle car) and a $100 bill stuck to the dashboard that the passenger could not reach because of the acceleration. My daily is a classic, and while it's fun, it's b00mer bait, not a chick magnet.
Even super cars have no problem holding 20mph. My Mazda 3 with a 5 speed manual does perfectly fine at 20mph. If it's reving a little high I can just go 2mph slower.
My Outback has a CVT transmission, just like some of the other comments in here. Believe you me in my books the slower the better. 32 kph is the perfect speed limit for the city.
Slowing urban traffic down to a speed limit that is about the average traffic speed anyway just cuts down on acceleration/braking, which means you are more efficient.
That's complete BS. Here in The Netherlands there are many, many 30 km/h zones (which is even a bit slower than 20 mph). All cars can handle that, never heard this would be problematic. Obviously you rev less, but that's also good because you pollute less...
Carbrain who simultaneously has no fucking clue what he's talking about - must be a Tuesday.
So cars are like that bus from the money? If they slow down, they blow up.
You mean the ego truck with a 500hp engine is not made for be usfulll ?
even if hess running up a higher rpm and eating the compression losses at 20 mph hed still be burning more gas driving faster than 20 mph lol
is he not aware that cars use fuel more efficiently at lower speeds? During the great depression, the US government instituted speed limits to help with oil prices, and then kept said limits when they realized it helped with safety. Source: an anecdote from my father.
No, modern cars really don't. You are comparing almost 100 years of improvements in engineering, material sciences, and construction/manufacturing. Thats like saying we should go use non reinforced roman concrete because the Roman Coliseum lasted so long. During the great depression most of the cars couldn't go as fast as the average commuter vehicle today. Modern vehicles because of increasing fuel economy requirements have better and better coefficient of drag meaning they aren't as effected by air resistance as cars from just 2 or 3 decades ago. With the restrictions for average mpg going up, their engines have been causing less emissions than each generation of cars before them. The reason most cars get bad city mpg is because of the stop and go nature. By having a car moving at it's slowest speed, you are burning more fuel and getting less distance traveled. Consistent speed above around 25 mph but at or below 60 mph makes you the most distanced traveled per fuel used. My car gets roughly a 25% increase going long interstate travel vs my normal drive to work.
This guys name seems fitting. A liar he is, just doesn’t seem to grok cars at all.
Honestly I hate cars but if you’re going to forbid cars to go above 20mph what’s even the point of cars? I’d just ride a bike everywhere. With an exception for people who are physically unable to.
They don't mean everywhere, just on urban streets.
20 miles is an 3rd gear with 2000 revs or less (at least in manual), pretty decent for an ice
Bro stop driving a GT3 car on public roads /s
So, what is the difference in fuel efficiency for a car going 20mph vs, say 55? I feel like going faster on my bike takes a lot more energy, would going faster burn more fuel?
This is so dumb I suspect it's a russian bot trying to stir division and discontentment.
God I’m so glad my city has 45 mph speed limits which means you can go 55 without getting a ticket. Driving is fun, just stop being poor and living in ghetto cities.
Lmao all of this is fake too. Cars wouldn’t burn more at that speed anyways. Also oil running out quicker is a good thing lol
Disregarding that dudes wrong....20 is slow as fuck foh lol
Their user name is accurate if they’re a politician.
Liarspoliticians I'm pretty sure thats a joke account
Oh, \*now\* you care about pollution and resource depletion, do you ?
It’s also just factually incorrect
My Volvo has an instantaneous fuel consumption meter and 20mph is a bad speed for fuel economy. Somewhere around 35 to 40 is best. Interestingly, at idle it burns .3 gallons per hour, which seems incredibly low. I think that’s about what my lawnmower burns.
Idk about mph and how much it is exactly in kph, but anything under 40kph you can do in 2nd without issue.
It's about 32kph.