Reaction time and car accident

There are 10 cars in a row, all moving in the the same direction with the same speed.

You are the  driver of the second car.

The average reaction of the driver is the value of the T= field +- 0.1 seconds.
The default is 0.5 s which means between 0.4 and 0.6s

You reaction time will determine if an accident will happen or not.
(and how many cars will be involved in the incident)


Subject:  Reaction time & car accident
Date:   Sun, 24 Oct 1999 21:00:03 +0100
From:  "Ray Holloway" <>
To:      <>


I have only just found your wonderful web-site & have tried the accident
experiment, it really is a good lesson for us drivers.Perhaps it should be
included in driving tests.
I had not appreciated the "knock on" effect until I noticed that although
I could stop in time those behind me could not.
I found that at 100 mph I had to allow 75 feet between cars for them all
to stop & even then it was not succesful every time.  A wet road would of
made it much worse.

Thanks for a very interesting site, although I have no formal education in
Physics I find it fascinating, so I am going to try the other experiments now.

Regards,  Ray Holloway

Your suggestions are highly appreciated! Please click

Author : Fu-Kwun Hwang, Dept. of physics, National Taiwan Normal University
Last modified :