Many crashes occur because one driver is too close to another. While the driver in the rear might claim the driver in front did something wrong, courts typically hold the person behind to blame.
You cannot see what is in front of the car traveling in front of you. Its driver may have to brake suddenly to avoid a dog that runs out in the road or swerve to avoid a pothole. Or, they might lose speed all of a sudden because of a battery fault.
None of these is a problem if you are far enough behind
If you are driving at a safe distance and paying full attention to the road, you can react to what the driver in front does rather than pile into the back of them. Measuring a safe distance in feet is quite difficult. Hence it is better to measure it in units of time.
You want to be at least 3 seconds behind
That is what the driving safety experts say. Pick a point on the road and count three seconds from when the back end of the car in front passes it. If you reach it under three seconds, you need to slow down as you are too close. You should increase this figure for driving at night or in poor visibility, or when the surface is greasy or covered in ice or water.
While this rule is simple, many drivers have not heard of it or do not practice it. If a driver rear-ends you, get legal help to show they were too close and seek compensation for your injuries.