At least 2. At freeway speed, 3-5.
it is recommende to keep a gap of at least two seconds behind the car in front of you so the distance varies with the speed
How many car lenghts does your car have to be when you are stopped at a red light? a minimum of 2 seconds behind the car in front
Three seconds is considered a safe distance to follow someone at. Here in California the Highway Patrol suggests four seconds. Any time you are following someone closer than is safe for the conditions, you could get a ticket.
2 seconds.
30 seconds
1 second
At least 3 to 5 seconds, that would be at least 4 to 6 car lengths going freeway speed.
93
The duration of King of Cars is 1800.0 seconds.
The duration of Z-Cars is 1500.0 seconds.
between 7 and 10 seconds according to the grade of the explosion
Safe distance is 2 seconds, or 4 car lengths. More if snow is on the ground or its raining.