In NJ, "safe following distance" is about 2 feet, but I always leave room, both when driving and when at a stop, so I can "help" the guy behind me stop in time.

A good rule of thumb is always stop such that you can see the bottom of the rear tires of the car in front of you. This way, you can pull around if need be and pull up if necessary.

Glad you are OK.

JCD