Click on 'GO' to start the tester. The one way sign will then change to a priority sign, to indicate that the tester is preparing to measure your reaction speed. After a few seconds the priority sign changes to a stop sign, which is when you should click on 'STOP' as quick as you can. Your reaction time will be shown on the license plate, measured in milli-seconds.
After you have played a bit with the reaction tester, you may be curious about how it works. A description of the principle of operation can be found here.
© 2020, Berend Meijer, all rights reserved.