That seems like a coincidence, that the relative velocity between the car and the fuel shooting through its injector should be approximately the same as the rel

That seems like a coincidence, that the relative velocity between the car and the fuel shooting through its injector should be approximately the same as the relative velocity between the car and the road. One could conceivably build a car with half-size injector nozzles that squirt in the same volume of fuel per unit time.