If a tire falls from a moving car on a highway, does the car keep on moving? I was driving and wondering: if my car's front right tire fells off while I'm driving on a highway, does the front right part of my car hits the floor (causing then a disastrous accident) or the car keep on moving forward until I can safely park it?
 A: A car is pretty stable on only three wheels, so long as you are driving fairly fast in a straight line.
However if you lose a front wheel on a front wheel drive car, you will lose the power to the other front wheel because the differential will just spin the wheel-less axle. This may also over-rev the engine and cause some collateral damage!
I know somebody who had this happen to a rear wheel on a motorway. One interesting thing is that the loose wheel overtook the car, because the tire radius increased when it wasn't supporting the car's weight. In fact seeing the wheel rolling down the road in front of the car was the first indication that anything had happened.
He successfully got out of the fast lane and onto the hard shoulder before attempting the slow down. The car stayed in its "normal" position until the speed had dropped to about 10 mph. There was no damage or injuries to anything except the car itself, and that was repairable.
A: This depends on the car and how the weight is distributed. Also, there is a difference between "tire" and "wheel". Your question is about the "tire". If the tire falls off (unlikely, but could if you drive it flat for long), but the wheel stays on, you could drive very slowly. Happened to me once, not a good experience. The wheel would be ruined most likely.
If the wheel falls off, then it depends on the car. This has happened to me once as well. I was rotating the wheels when my brother had a medical emergency and I had to take him to a hospital. In a rush, I overlooked that I only had one of four nuts on one wheel. While stopping at a street light, I heard a metal noise and saw a wheel passing us by spinning forward. I thought, "What idiot has lost a wheel?" just before realizing that it was me. It took me a minute to put it back, so a happy ending, but in the meanwhile my car was down to the ground and would not drive on 3 wheels.
My most fascinating 3-wheel experience was when I was passing a pick-up truck speeding 60 mph on a remote narrow highway in Russia. The truck had a heavy load in the trunk shifted all the way to the right that seemed strange. As I was passing the truck, I saw that it did not have the left front wheel, but was speeding on 3 wheels. Th load in the trunk was balancing the truck to compensate.
It's not a good idea to drive on three wheels, unless you life depends on it.
