The answer to this question is that --- The momentum possessed by a body is generally defined as the product of its mass and velocity.
Momentum is a vector and it also has magnitude as it is the product of the multiplication of the mass and velocity.
Newtons 1st law of motion states that the object will continue to move at its present speed and direction until an outside force acts upon it.
So unless the objects inside the car are restrained, they will continue moving at whatever speed the car is traveling at, even if the car is stopped by a crash.
Answer: It wouldn't be as modern as today is we would be back to using oil and other things from back then there wouldn't be cars everything would be less machined.
