Yes, all cars ecxept "special" ones (police, swat, etc.)
I don't know
They do now.Should cars have built-in speed limit?
I can't get my 86 CRX SI to go any faster than 110 mph!
What maximum speed should be placed on a divided highway with wide shoulders and two well-paved lanes in each direction? There is no single answer. What is the experience and ability of the driver? What is the capability of the vehicle? What are the environmental conditions of the roadway? What is the traffic density? What time of day/night is it?
This thought process applies to each and every road on the face of the planet. Without the consistent intrusion by nanny states the world over, people would constantly adjust their speed and driving style to the situation. Prohibitions on movement (i.e. stop signs, traffic lights, speed limits, etc.) only serve to create the opposite mentality which reduces awareness. When a person sees a green traffic light in front of him, he knows he has the right-of-way and need not observe cross traffic. Yet how many accidents are caused by people inadvertently (or purposefully) running red lights? Without a government implied right-of-way, drivers would necessarily have to adjust to the flow of traffic and treat cross traffic as a potential hazard.
For example: it's the perfect weather - the sun is shining (not too much), the road is dry and empty, the car is in great shape, you're in great shape. You decide to go for a spin and punch it. You reach 100mph. And then... a flat tire, dang! Or a deer on the road. Or a car accident around the corner... Are you telling me there is no difference between driving with 60 and 100 mph?
That's not how automobile computers work anymore. They are measuring everything - tire rotation between the tires, indicated speed, engine rpms and transmission gearing. Governors can control available power, rpms, the gear the car is in, speed, torque, horsepower and factor that in to many variables. You're thinking of an rpm-limiter.
If SAFETY is the issue, all sub-compacts should absolutely be outlawed. They are proven very deadly in accidents either with objects or other vehicles.
Speed limit standards were set decades ago - when cars had crap for brakes, suspension, tires and safety equipment.