Each interval increment is approximately.5 seconds. A setting of 7 equates to a little over 300 feet at 60 mph which seems like a lot. However, it takes about 1.5 seconds for the average person to recognize an event ahead, decide how to react and begin to execute their reaction. This leaves about 2 seconds to stop for example. The result is a car that takes about 150 feet to stop at 60 barely avoiding a rear end collision. This supports the ability to opt for greater interval options for more cautious drivers.