The rule of thumb is one car length for every 10 miles per an hour that the car you are driving is traveling.
For example:
You are traveling 70 miles an hour on the interstate, the car you are following should be seven car lengths ahead of you.
The rule that i always follow, is 3 seconds behind the car ahead of you !!
When driving, you should always measure your following distance in seconds. A general rule of thumb is to maintain a following distance of at least 3-4 seconds between your vehicle and the one in front of you. This distance allows you enough time to react and brake safely in case of an emergency.
car lengths
You can't measure that..... Los Angeles is already in California!
3 sec
A direct line between the two cities would measure 3789 kilometres or 2354.4 miles. Using current roads, if driving, the shortest distance between them is 4702.6 kilometres of 2922.1 miles.
It depends on how long a distance you want to measure!
Displacement is a measure of distance. Speed is a measure of the RATE at which the distance is traversed.
Seconds
You should always measure your following distance by car length. This will give yourself time to break when necessary without being close to the driver ahead of you.
Angstroms
With maths and light brightness.... Distance between two points...
The distance between places.