The study of the human trait of maintaining of the distance between cars

The stability of car-following was examined utilizing a newly developed recorder of the distance between cars. Eight undergraduate and graduate school students (seven men, one woman) joined this experiment. At varying speeds, the drivers followed the lead car under the instructions of maintaining a 15 m distance between cars, maintaining the distance by counting one second mentally,and then again maintaining the distance by counting the beats on a metronome set at one-second intervals. Results showed the most stability of driving under the instruction of the metronome with one-second intervals at varying speeds. Similar results were achieved under the instructions of the metronome with three-second intervals at varying speeds. Introducing a device which provides a driver with an objective count seems to be effective in the maintenance of a stable distance between cars.