Ask HN: Why do they make cars go so fast if it’s illegal?
Disclaimer: IANAL, but also asked that question once in my youth, and went digging for the answer.
They technically don't in a meaningful sense.
What they do is make a car that has high torque and can accelerate 0-60 mph as quickly as possible. This has the unwanted side effect of also being able to still continue accelerating quickly past the target zone (<= 85mph). Some street legal cars have governors because of how exceptional their acceleration is.
The acceleration in cars are designed around pretty much one extra horrible edge case: accelerating up to freeway speeds, up an onramp that is entirely too steep (yet legally designed), from a standstill (ie, gridlock conditions), while also carrying max cargo capacity. Cars must be able to do this to be considered safe by any meaningful definition.
Also, there are no laws against going fast. The laws are purely against the law on public roads, as per the posted limit; there are many private racetracks that are completely legal. Not all countries even have limits comparable to America's, so being able to safely go 100+ mph is worth it if you were to, say, drive on the German Autobahn.
A bit of a pet-peeve of mine, but it is the power that makes the car accelerate, not torque. With gearing, any value of torque is possible at the wheels, but not for any given speed. A car with 300 Nm of torque but 100 kW of power will never accelerate faster than the same car, but with less Nm and say 150 kW of power. Gearing is suitably chosen according to power production, not torque. The answer to the question "At what RPM will I accelerate the fastest, for a given speed" is always the RPM at which peak power is produced - which may or may not be avaliable because of gearing, but usually you can come pretty close since the power curve is somewhat flat around a region of RPM. Typically.
Exactly. E.g. Diesel engines have a much lower maximum rpm limit (4.5-5.5k rpms) so they need to deliver that amount of power by delivering more torque at lower RPMs when compared to comparably powered petrol engines.
And electric car motors can draw almost maximum Amperes at very low rpms, hence the insane numbers of torque for electric cars
"Some street legal cars have governors because of how exceptional their acceleration is."
Most manufacturer limits on top speed are tied to the vehicle tire speed rating (usually somewhere around 92-116mph). There are a few that are sort of an industry standard cutoff for 'safety', like 300kpm (I think) on sport bikes.
> the German Autobahn
Since this meme comes up a lot: About two thirds of the Autobahn network do have speed limits, ranging between 80-130 km/h (50-80 mph). In fact, one of the arguments for a general 130 km/h speed limit is that it would reduce the rate of speed limit changes, thus making traffic flow smoother overall.
There are a lot of ways to interpret this question, as shown in by the variety of responses in this thread.
But we could rephrase it to "why aren't top speeds limited to the maximum speed limit?".
It's got me thinking about the creeping culture of safetyism, especially against the current backdrop of Covid-related restrictions.
In some ways it makes no sense that cars are not restricted to a sensible top speed. Either a simple dumb limiter set to the top speed limit for the country, or something more sophisticated using GPS (or a combination of the two). Doing so would possibly (probably?) save many lives per year. Yet it's unlikely to happen because:
1. there's a powerful automotive industry that relies on cars retaining their power as a status symbol
2. there are a lot of powerful and influential people who enjoy driving fast cars.
It frightens me that we are seemingly only able to retain our freedoms when there is some powerful industrial lobby to protect them.
People are currently being subjected to much, much greater restrictions of freedom than having the top speed of their car capped. Entire livelihoods are being destroyed on the basis of "saving lives". Perhaps this is justified. I personally don't think so but a convincing argument can be made.
If there's a conclusion to this, it's that we need to move past the "if it saves some lives, it's worth it" style of argument.
It sounds brutal, but some values are worth holding on to even if they kill people. You may balk at that statement, but you implicitly accept that compromise every day, even if you've never explicitly thought about it.
Don't some of the higher powered cars in Japan have a GPS system that won't allow them to exceed certain street limits?
Places that have some roads with unrestricted speed probably wouldn't be a candidate for non-GPS blanket restrictions (Germany has the autobahn, Montana has/had some roads posted as 'reasonable speed').
There is also the argument against both types of restrictions that some situations can warrant excess speeds. If you are speeding to a hospital because your neighbor has potentially life threatening injuries from being run over by a tractor, most states have a clause that allows you to break the laws to avoid greater harm in situations like this.
The best answer I know of so far is to increase driver test requirements in the US. Many European countries have more stringent testing with lower fatalities per million miles, even when comparing US interstates to the German autobahn. The number of drivers I witness who make bad decisions or don't know the law is quite high.
To sell them to people who want to go fast or want to have the possibility to go fast, but it also used to be for technical reasons.
Most cars have a gaz engine and the efficiency of a gaz engine is not linear. To simplify, an engine often has its best efficiency around 2000rpm and can rotate as fast as 6500rpm but it will then waste a lot of energy, mostly in heat. You want the engine to operate at its best efficiency when you drive normally. So you design the gearbox accordingly, to get 2000rpm at 130km/h for example. But the engine can rotate faster, and therefore you can drive faster than the speed limit.
You can limit how fast the engines rotates, most engines do have a limit around 6500rpm, but if you limit the rotation speed, the cars will lack a lot of power. The power is the torque of the engine (how strong it can rotate) multiplied by the rotation speed. So limiting the rotation speed is quite a problem. Many people prefer to buy powerful cars. They don't even know about the torque.
You could limit how fast the engine rotates once you reach the speed limit, but for a long time this kind of technology was quite complex and expensive. Nowadays, since maybe 25 years, it's totally fine and cheap to do so. Some German brands put an electronic at 250km/h on their fast cars for example.
With electric cars it's another story and while most don't go very fast, mine goes up to 150km/h for example, some are fast only to sell them to people who want fast cars.
Today we could definitely put a limit at the legal speed limit, based on GPS and map data and for example, but many people would complain and some would buy a car without the limit. I think the only solution is to force all the constructors to do implement a speed limit at the same time.
Russian?
Tracks, private roads, autobahns, dynos, plenty of places to go fast legally.
Not to mention the extra power goes towards faster acceleration, not just top speed. The same force that gets you an extra 10mph top speed also works to get you from from 0-60mph that much faster.
Especially Autobahn in Germany is interesting. Generally there is no speed limit, but something called "Richtgeschwindigkeit" (the advised speed you should go, which is 130km/h). But there ARE speed limits on most parts of the Autobahn (construction sites are generally limited to 60 or 80km/h, dangerous sections, etc. so it's often limited to 100-140 km/h). Sections without speed limit are a lot of fun and created a whole industry around them. There are car rentals with sports cars you can get for a few hundred/thousand Euro a day, depending on the car (and they have almost everything, from Porsche and Mercedes AMG to Ferraris and Lamborghinis).
As someone living near a luxury car rental place (but in a country with a national speed limit), I want to point out that the main target audience for renting Lamborghinis and Ferraris isn't passionate drivers.
It's 28 year old males with money and no sense of self-worth. There are regularly reports of people doing nothing but driving up and down a nice street downtown. Flooring it from red light to red light, dropping the clutch on every gear change. All. Day.
The completely unrelated question I would like to ask is "Why is it allowed to show your middle finger to random people on the street, but as soon as they're in a car, it's a crime?"
Woah it's a crime to flip someone off in a car in Germany? TIL
It's also a crime to insult people outside of cars in germany. When doing so behind the steering wheel it may result in a temporary driving ban in addition to a penalty.
IANAL, but in the German legal system, one can only be convicted on an insult charge if the insulted party explicitly requests it.
Behind the steering wheel, the situation is different because road rage will usually not be litigated as an insult, but as attempted coercion.
We should add that traffic flow on normal days will prevent you from going _real fast_ for longer durations. People who try that will regularly provoke dangerous situations.
A general speed limit on the Autobahn is long overdue. Lots of our neighbours (see Austria, Switzerland, Netherlands, Italy) are doing fine that way.
Of course, street-legal automobiles could simply be governed with a top speed of the fastest legal speed limit in a given region.
How do you imagine this working for someone who drives across Europe frequently, including sections of unrestricted Autobahn? Or someone who takes their street legal car onto (private) tracks from time to time?
wait, so now all cars in the world have to optimize for a fraction of roads in Germany? or having a universal ability for everyone to take their Chrysler Pacifica or Chevy Equinox to a private race track? This explanation makes zero sense, tons (if not most) of cars that have 120-140 mph on the dashboard (such as the two above) will never go anywhere near Germany or a private race track. I'd rather go for the "acceleration" explanation elsewhere here - but what do I know.
Limit it to 130 km/h, which is appropriate for almost all or Europe[1]. If you're e.g. in Germany or Poland, you can have it unlocked, but the car stops being road legal anywhere else.
Ideally, they'd just harmonize the speed limit in the EU; a majority in Germany approves of introducing a general speed limit on motorways anyways. But that'd hurt the bottom line of car manufacturers and we can't have that.
Also, GPS-validated speed limits for new cars. And I don't mean just the top speed in a country, I mean the posted speed limit on whatever road you are. Doesn't need to be a hard limit, in case of emergencies and for maneuvering, but make something interesting happen: online registration, enable the hazard lights, I'm sure there are many good options. It's ridiculous we're talking about fully automated driving and we don't even have this simple automation which would get rid of an entire class of everyday offense.
[1] https://de.wikipedia.org/wiki/Datei:Freeway_speed_limits_eur...
All new cars sold from May 2022 in the EU will be fited with intelligent speed assistance systems (sign recognition etc) with speed limiters.
https://www.europarl.europa.eu/news/en/press-room/20190410IP...
Interesting, thank you. Just a feedback mechanism, not a limiter, though. And I imagine you'll be able to turn it off...
GPS :)
But then you need an up-to-date database of allowed speeds on roads all over the world, and since those already aren't reliable when they're used as indicative data, I don't think that's a viable solution.
It also wouldn't work on road sections with variable speed.
Doesn't need to work everywhere for it to be useful. You can always fail fast, literally. The data is available for wide swathes of Europe, for example. Last time I checked it was very accurate even for temporary construction sites.
Variable speed roads, either make the limit the highest speed that's in the range, or come up with a way to communicate the current limit. Most new cars are always connected, anyways. And again, you can fail fast, at least initially. As with all driving aids, the person in the driver's seat bears the ultimate responsibility.
Yet failing anywhere can be dangerous, even fatal.
An example: A construction site goes away, raising the speed from 35 to 70mph. Someone governed to 35 is suddenly a virtually stationary obstacle. Theoretically (and legally), the onus is on the other drivers to avoid it, but practically speaking it's just begging for an accident.
Can't remember where I read this but IIRC it's not a healthy for a machine to constantly run at 100%, hence you make an engine with a peak performance of 200mph which constantly runs at a cosy speed of 100mph.
Though for a diesel engine, at least, it's also not healthy always to run at 50% - there's been a significant problem in recent years with boat-owners on UK waterways over-specifying the engine they need for low-speed cruising, and suffering glazed bores as a result. http://coxeng.co.uk/engine/bore-glazing-and-polishing-in-die...
Good point.
Fossil cars are also more efficient at lower RPMs. Designing the gears such that they can cruise at highway speeds with low RPMs incidentally allows the cars to go way past speed limits as well, if they have enough extra power.
Well, that depends on the exact model/make. In Germany there's the term "vollgasfest" (full throttle proof) for cars and it means ability to e.g. empty the gas tank in the pedal-down position in one go without damage. Especially some of the foreign brands from the 70'/80's are known to overheat in such conditions and also some of the earlier turbos. Wear is of course increased under more load but i wouldn't regard it unhealthy for engine/transmission and co per se.
From May 2022 all new cars (and buses etc) sold in EU will be fitted with "Intelligent speed assistance (ISA)" systems. ISA meaning sign recognition or other means of detecting the legal speed limit, that limits engine power when the limit is exceeded [1, 2].
The European Transport Safety Council (ETSC), the body which supports the introduction of ISAs, says the limiters would reduce collisions by 30%, and save around 25,000 lives within 15 years.
I think this is a really brave move by the EU, and a great example of use of technology to save human lives. I wonder if these kinds of "unpopular" legislations are rarely be made by local governments filled with politicians up for re-election every four years as it spells doom for chances re-election.
1. https://www.europarl.europa.eu/news/en/press-room/20190410IP...
2. https://www.rac.co.uk/drive/news/motoring-news/mandatory-spe...
Because it's not illegal to own or sell a car that can go over the speed limit.
A speed limiter is a feature that prevents a vehicle from doing something that many potential buyers want it to be able to do. There's absolutely no incentive to build in one that can't be disabled. In contrast, ones that can be optionally enabled are common - my car has such a feature, and I often enable it for sections of road with average speed checks.
Generally because machines should serve us instead of telling us what to do. This is an important principle for many of us.
That said I generally stick to the speed limits [1], but what if I need to get to the hospital in a hurry? At least around here local laws are quite clear that you are allowed to break laws and regulations to save lives.
[1]: old habit, wasn't always a well paid programmer and also I mostly think it is the right thing to do :-)
We could have speed governors with an opt-out button, where use of the opt-out button gets logged and has to be justified.
This can be a good idea in certain applications, but the idea of applying it generally comes off as outright scary to me.
What history, politics and leadership classes at school (as well as following the news for a couple of decades afterwards) has told me is that such tools should be used to protect ordinary citizens against abuse of power, not to simplify the lives of those in power.
Otherwise we should just as well make it mandatory that everyone wears GPS trackers and has cameras installed in their living rooms as that should certainly reduce unsolved crimes ;-)
(To make it clear: I support the police, at least our local police, but I still think they should be logged whenever they do something at work that ordinary citizens aren't allowed to while ordinary citizens - and off duty cops for that matter - should only be logged after a judge has allowed it for the investigation of a specific case.)
Edit:
A very practical example: 3 kilometers down the road next to me there is work going on, so instead of 80 km/h the limit is 30km/h.
All well and good except the speed limit doesn't stop until a few hundred meters after the roadworks. Almost everyone breaks the speed limit here, or can we just accept that sometimes people have good reasons for breaking the rules?
Do we want all that information in the hands of already powerful people so that they can selectively enforce it against their enemies? (admittedly less of a problem here in Norway, but you catch my drift).
I didn't have cases like your example in mind. If you couldn't know that the speed limit would decrease soon, eg you had no idea the speed limit was going to change until you were nearly level with the sign, then presumably the law should require you to slow down promptly but safely. The opt-out button shouldn't be required in that case.
The opt-out button would be for rare situations where you actually need to exceed the speed limit for reasons of health or safety.
I don't want information getting into the hands of powerful people without a very good reason, but I think the safety benefits of universal speed limit compliance with exceptions for health and safety would constitute a very good reason.
In terms of privacy, this idea seems more or less equivalent to traffic cameras that capture images of license plates when drivers fail to comply with traffic signals.
Some drive cars on race tracks where it is legal. Also some roads have high speed limits like ones in Germany.
In Germany there is no speed limit on highways.
*small sections of some highways
70% of the Autobahn is unrestricted, that is not a small section.
That's surprising as it certainly feels like more of it is restricted when driving on it. If you drive the autobahn you will curse that any of it is unrestricted. There is enough changing between limits and no limits to create additional cognitive load. It seems like more than 30% is restricted as time traveled on the unrestricted bits is less per km. I never received more speeding fines in my life than when I drove from Berlin to Austria and back.
A lot of German highways do have speed limits. I have driven from Norway to the UK and back several times over the last three years via Germany, I think that probably only half the motorway driving in Germany was unrestricted. And even where it is technically unrestricted the traffic is so heavy during the rush hour that you can sometimes walk faster. I have Hamburg and its perennial roadworks in mind.
About 70% are without a speed limit in Germany https://de.statista.com/infografik/16725/tempolimitregelunge...
I assume if cars where invented today, there would probably be digital speed caps on cars in most countries.
What would you make the top speed? When I was a kid the speed limit was 55mph (100kmh). Then they raised it. Some states the speed limit goes up to 75mph, while in others it is 65. There is talk of going faster in some states. (and I might not even be aware of the rules in all states)
I think the big thing is acceleration, if you've ever tried a motorcycle you'll understand.
I would appreciate having a mode on my car that automatically sets the governor to not exceed the speed limit as found with GPS. I could turn that off if I really need to and otherwise not have to think about the speed limit.
A lot of newer cars have this already. There's an EU draft law approved for this to become mandatory for all new cars from 2022
Fast cars are expensive. Germany wants to sell A LOT of expensive cars. But there is a problem: in most countries fast cars are illegal. So how to solve this problem? German carmakers tells about this problem to the German government. German government finds a solution: allow unlimited speed on German highways so we can make fast cars legal - at least in Germany. Now "they make cars go so fast" and they are legal - in Germany. Now rich people order fast, expensive cars - from Germany. Officially they will not drive them too fast in their countries. Buy everybody can imagine, what happens inofficially... they have enough money to pay for the penalties (with the exception of Finland and maybe some other countries, where penalties are percentage of your income).
Fast cars are not illegal...
The speed of cars mostly comes down to how much power they have. The main reason for having more power is not to increase top speed, which is limited by law, but to increase acceleration, which is not.
And now a days, bragging rights. People like speed - period. If 1 model out performs another model at a similar price tag and features / design - people will go with the faster one (usually). Same as any other personal preference - people shop with their eyes first, wallets second. If they like speed, that sells more cars.
It's nice to feel high torque. (And high torque is not illegal per se)
Driving a car that doesn't accelerate well while hearing a sound like you are hurting your engine is unpleasant, even for passengers.
* Moving slowly onto the freeway is extremely unsafe
* Passing someone slowly is extremely unsafe
* Sometimes evasive maneuvers require accelerating rather than braking to avoid danger
Is it? I can legally drive at any speed on most highways around me, and yes I do drive 260 km/h daily (fifth year without any accident btw).
If you had any you wouldn't be here to post about it.
Hmm... I've seen a few high-speed accidents less than 15 minutes after it happened. People were mostly standing on their own legs, except for that one car that hit a tree at high speed even though it was pretty far from the highway (that was ugly). High speed accidents can be and very often are fatal, but it's not as absolute as you're saying.
It's all about the car - don't drive 260 in an Octavia, not even a Passat, much less a second-hand one. Recent Mercedes E-class with all the additional safety equipment can handle high speed crashes well, and the automated systems can do a lot for prevention as well as saving the situation (but there aren't many situations that need saving with the prevention systems).
BTW going 260 in a Mercedes feels about as controlled and smooth as going 70 with less expensive cars. It really is something totally different, and you have to feel it to truly understand it.
The higher gear ratios allow lower fuel consumption, less vibration, lower cabin noise, and plenty of reserve power for overtaking or towing.
In Argentina some of our public buses have a rev limiter, since the limit is lower for them (up to 60km/h).
1) There are different speed limits on different roads. If you put an artificial limit on how fast your car could go, it would still go illegally fast on slower roads.
2) Speed limits change. It would be a hassle (understatement of the week) to update every single car.
3) As others have said, you can always drive legally on private tracks.
You could nowadays easily imagine a GPS-based governor according to the speed limit of the road you're on...
Sure, and I can also easily imagine many ways in which it fails :)
It isn't illegal everywhere.
Acceleration is a big part of the enjoyment of fast cars. That's not usually illegal.
Also, having better acceleration can help reduce the 'time exposed to danger' when overtaking, which may still be below the local speed limit. Faster cars can be safer, see...
You may be conflating acceleration with velocity?
Acceleration is definitely helpful (to a point , even on the track), but for instance I live in the UK where the max speed limit is 70mph, and my very ordinary car is specced to do more than double that. I don’t see the benefit of being about to do >>100mph outweighing the risks- earlier comment mentions how this arises from the need for useful torque bands in IC engines which explains a lot and makes perfect sense, but with modern engine controllers and especially electric I agree that this is no longer necessary to leave enabled in the vast majority of vehicles.
Can your very ordinary car maintain that top speed at a maximum duty cycle without overheating or causing unnecessary wear to the engine or drivetrain? Have you ever actually used your car at its limits? It's not something that you would want to do for long periods of time. Now imagine your cars limit is 70mph.
No but this is why you would use a speed limiter rather than changing the engine. This is already done on every HGV in the country and most mopeds.
The most simple answer:
Because people are willing to buy them.
It also supports typical human behavior. If you're neighbor has a 400hp car, to "one up" them you buy a 500hp car.
Childish? Yes. Are adults with childish behavior new to the human race? Not at all :)
It is legal to accelerate from 0 to 100Kph very quickly
In Minnesota at least we “unlawful acceleration” / “unreasonable acceleration” statute. I have a couple friends who have received tickets for it.
I didn't know about this, I think we don't have this in France
If a cop catches you driving like a tool, they can give you a reckless driving ticket even if you didn't break the speed limit.
Eleanor Lily. Welcome to the war on cars.
I used to think about this a lot when I was younger, because it makes very little sense, and as I became older I realized how many more things make very little sense and I eventually came to realize the bug is low-level and there are a lot of rich and powerful people who do not want it to be fixed, because it allows for them to exploit everybody else.
Why do they make keyboards that can type hate crime? Why do they make cameras that can shoot child porn? This is possibly the worst question I've seen in this site.
There was an interesting Radiolab recently where they talked about how the Chinese IMEs are shaping what people say and can say. It’s a genuine fear that such control could happen.
Your answer is wrong and insulting, Since you probably know most new cars have optional speed limit and GPS then it is very logical to ask why not make them opt-out then opt-in.
Now you could attempt to give a fair answer why you think this is hard to implement correctly or why is a bad idea.
Also we could theoretically install something that can detect if the driver is tired,drunk or not paying attention. There is no requirement that police or government must be involved , maybe in some countries you can implement and solve this with free market , insurance and all that good capitalistic/freedom stuff.
I think lot of people here are going to disagree with me but seems to me there's a case for putting limiters on cars.
Drivers sometimes hit other vehicles. Airbags go a long way here. Sadly, drivers will often hit less fortunate road users such as pedestrians and cyclists.
We already know that pedestrians hit at 30 km/h vs. 50 km/h stand a much better chance to survive. Sadly, cities are rarely designed for 30, and usually more 50+, depending on the city.
Changing cities is, well, possible, but also kind of difficult and unpopular. You know what's easier? Making car manufacturers limit cars' speeds in cities.
It's not technologically difficult. Lots of new cars already read speed signs. Almost all of them have some sort of GPS component.
Geofencing speed limits seems like a pretty easy fix compared to the infrastructure changes of traffic calming (which we should do anyway). You can make it opt-out (and non-trivial enough to do so) so that most new cars on the road have these limits at least in cities.
Does this sound crazy? I'd argue it isn't. Consider that E-bikes/E-scooters are limited to 25km/h in a lot of countries. Similar story with small 50cc scooters. In some places rental E-scooters even have geofenced speed limits already, and the Netherlands is considering a similar plan for E-bikes (ones owned by ordinary citizens).
While this is theoretically a good idea, in practice there's a lot of hard questions without good answers.
Where does a city begin? End?
Should we cover the suburbs with the geofence?
What about the beltways or highways that go through the city?
In big cities, GPS is spotty or completely unavailable, what do we do there?
What about city streets which pass under/over highways?
As I've pointed out in other replies, there isn't a good enough, when forcing cars to slow down significantly. Road conditions and surrounding traffic speeds make any unexpected slowdowns ripe for creating accidents.
I don't know where you live but city limits are very clearly defined in many places. Here for example, there are clear designations (that are reflected in a default speed limit too).
I don't quite know what your (American?) suburbs look like, but in theory I don't see why not in this instance.
And if you're concerned about, idk, people not being able to get to the hospital on time or what have you, make them opt-out on every single ignition. Most people will probably not be bothered to opt-out every single time.
As for the technical points regarding GPS, lots of cars already read speed signs and come with various computer vision based safety features.
Again, ebikes and escooters are already speed limited and geofenced. It's not perfect, but why aren't we so concerned about ebikes being slow and not being able to keep up with cars and subsequently be hit by them?
Lastly - it doesn't have to come into full effect if you're at 120km/h. You can be smart about it, like not slowing you down but not letting you accelerate, easing you into the speed limit etc.
There's a perception that cars are a fact of life and it's OK for them to be traveling at speed in cities, whereas the reality is that in most urban areas we simply cannot afford to keep this up any longer.