Why are the majority of cars able to drive nearly double the maximum speed limit of most countries?
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None of the answers here are correct. You can have a V12 700+ horsepower engine and still put an ECU limiter at 89 mph, same as the limiter on the cruise control systems every car has.
The reason manufactures don’t put it isn’t true either, they most certainly do. Here in California, most cars are ECU limited at 155mph and a few will reach 172mph. You can of course unlock these limits through ECU mods but that’s probably illegal.
Can manufacturer’s add ECU limits at 89mph like they do on cruise control systems? Yes.
Why don’t they? Because there is no law requiring it so if BMW implemented this they would just lose business to Mercedes.
People like being able to accelerate quickly… Both for vanity and for practicality. They also like driving large, heavy cars. Again, for both practicality and vanity. They also like cars that get pretty good fuel efficiency. So the cars have to be very powerful in order to accelerate quickly, but they also have to be very aerodynamic. Having a lot of power and very low drag means that they can also go very high speeds.
Most cars are electronically limited to much lower than their functional top speed for a number of practical and safety reasons.
If the car is capable of operating at a higher level than is typically asked of it, then it will operate in its normal conditions much much more efficiently. Also sometimes it’s better to speed up away from a hazard than slow down depending on circumstances. If your car is operating at 100% of its ability all the time at normal speeds and conditions, you’re gonna have a bad time when something unexpected happens.
When it’s getting close to its maximum physical speed, a car’s performance gets bad. It’s efficiency goes down, and it’s acceleration is terrible, taking forever to slowly creep up a little faster. Driving it in those conditions for too long is bad for the car, burns through fuel like mad, and gives you no wiggle room for accel/deccel maneuvers if there’s an emergency need to do so.
So the car’s max sustainable cruising speed is quite a bit lower than its maximum possible temporary speed. Since the cruise speed is always lower than the max speed, designing a car that can cruise at the legal limit all day on the open highway also means having to accept that the car’s max temporary speed will end up being well over the legal limit.
And as long as the car *can* temporarily go that fast, they may as well make the speedometer capable of measuring it, since it’s better to have the information and not need it than the other way around.
The real question is why isn’t this speed limit higher in some places?
As a German here, I have to ask:
What speed limit? (SCNR – and yes, I can and did drive regularly at speeds in excess of 200km/h).
Because limits were set a long time ago when cars were slower and unsafe. And there is no initiative to raise them.
At least outside the cities on highways they could be higher.
Inside cities it is due to braking distance.
My wife’s 2019 Kia Sorento’s speedometer goes up to 160 mph. The top speed limit around where I live is 70 on the interstate. I seriously doubt that Sorrento is going to hit 160 mi an hour even if the speed limit was 160.
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