# Why are normal street cars able to go over 100 mph if the highest speed limit is 65 mph?

Why not just design the cars to go 80 mph at most to prevent speeding?

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• Neil
Lv 7
1 week ago

Partly it is bragging rights, particularly among supercars - although the top speed of many supercars is so academic now because there are no roads with long enough straights and no restrictions for the top speeds to be reached.

For more normal cars, there are places where there are no speed limits, and speeds of 120mph or more are expected - particularly Germany's Autobahnen. A manufacturer restricting their cars to 80mph or less in Germany would see their sales fall.

But there is also an simple engineering function of the characteristics of internal combustion engines and the need for multiple gears. In order to get the desired acceleration and performance when climbing hills a certain power output is required, combined with particular gearing. To get acceptable cruising refinement and fuel economy, much higher gearing is required. The combination of the output required for acceleration and hill-climbing with the gearing needed for cruising mathematically leads to a high top speed almost as a side-effect.

However this is a result of the use of internal combustion engines. With electrically-driven cars the need for multiple gears disappears, so the acceleration and hill-climbing performance is provided without the side-effect of the high top speed. Speeds still remain above 80mph, but except for supercars the speeds are considerably lower than for equivalent combustion-engined cars.

• 5 days ago

You don't want to build a car that is maxed out at 65 - oh, and there are places (mostly out in the middle of nowhere) in the US where the speed limit is 75, 80, and in one place in Texas it is 85).

It's mostly about bragging rights, and the desire to have a fast car - although some vehicles come from other countries that have higher speed limits, including some places that have no real speed limit at all.

• 6 days ago

Because it you make a car able to drive 65 mph up a hill then it can probably do 100 mph going down the other side of the hill. You would need to put in some sort of a limiter that at the moment is not compulsory.

Also if you want to overtake a car doing 60 mph the more power output your car has the quicker it can accelerate and pass the slower car and safely get back in lane and continue at 65 mph. This is important in two way traffic and the gap between oncoming cars may be limited.

• Anonymous
1 week ago

Highway driving is not the killer.  Driving into intersections and not knowing the rules is where most accidents occur. So, in town.  Ask the insurance industry for the statistics on accidents.  Where, why and the reason for it.

• 1 week ago

Bragging rights? Also many cars are also sold in Germany. Some roads there have no speed limits.

• F
Lv 6
1 week ago

Yeh ,top speeds are pointless, my car will do 150mph but I’ve only once done over 100.

• Kenny
Lv 7
1 week ago

Manufacturers are not law makers and different areas have different laws.

• Anton
Lv 6
1 week ago

People will still be able to exceed the posted speeds on the vast majority of roads -- city streets.

If you power a vehicle to be limited to 80mph, it would go up hills doing 50mph, at best.  Since all of the existing vehicles will be able to do 65mph, the new cars will be slow and will be blocking traffic -- causing road rage and increasing collisions.

The other way to limit speed is by RPM limiters, such as my Vespa does.  At speed, the vehicle keeps missing, the engine going on and cutting off, over and over.  Trust me, very annoying.  It is TRIVIAL to disable RPM limiters.

The manufacturers build what people want.  The only to limit the speed would be law.  The vast of majority of people would not buy new vehicles, the car manufacturers would go out of business.  Since the government does not to lose manufacturers and taxes, NO ONE will make such a law, or make a such wimpy vehicle.

AND you are either a damn liar, or totally stupid.  The fastest speed limits in the U.S. is not 65MPH.  It is not 70MPH.  It is not 75MPH.  It is not even 80MPH.  Currently highest posted speed limit is 85MPH, on Texas Highway 130.

Now that you have been told why your stupid suggestion is actually really stupid, will you stop?

• Asep
Lv 5
1 week agoReport

Literally no reason to be calling me stupid, just making an estimate.

• 1 week ago

to outrun the cops