One car length for every ten miles per hour is a rule, two seconds is another rule, but in the rain, 3-5 seconds. Pick out a stationary object on the road as you drive. When the car ahead of you passes that object, start counting; you shouldn't reach that object until five seconds have passed. A good rule is you should feel comfortable about having a smooth stop if that car suddenly brakes hard. If this is for a motor vehicle test, I'd say 3-5 seconds.
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
Six car lengths is a good distance.
Safe distance is 2 seconds, or 4 car lengths. More if snow is on the ground or its raining.
One car length for every 10 miles per hour.
I always heard of the two second rule but I am not sure if that is law.
1m
one car length per 10 miles per hour
A safe distance, there is no defined limits of this type as driving near parked cars is situational (at best).
One car length for every 10 miles per hour of speed.
Know your distance between cars, fire hydrants and railroad crossing. These are the most over looked.
The distance between them is closing at (20 + 30) = 50 mph.It will close 1 mile after (1/50th) of an hour = 72 seconds
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.