Traffic signals and driver reaction time

Question

Traffic signals and driver reaction time

pwht1 (Structural)

(OP)

18 Mar 12 18:44

Hi all,

I'm trying to work out the average/85 percentile reaction time for drivers responding to a green light at a set of traffic signals.

My hunch says about 0.7 seconds and google seems to verify that, but I can't find any 'accepted' time in traffic guides i.e Austroads/RTA/Roads ACT. Does anyone know of standard which gives justified reaction times for traffic signals?

Thanks,
Paul

msquared48 (Structural) · Answer 1 · 2012-03-18 18:48:52

Depends whether the driver is a teenager or not.

Then again, adults like Don "The Snake" Prudomme would skew the curve.

Mike McCann
MMC Engineering
http://mmcengineering.tripod.com

dik (Structural) · Answer 2 · 2012-03-18 19:07:10

I seem to recall that there was a formula for determining the length of time required for an amber light...

Dik

pwht1 (Structural) · Answer 3 · 2012-03-18 19:19:21

Hi dik,

Yep yep, definately a formula for amber lights. The reaction times given in those guidelines are in the order of 1.5 - 2.5 seconds. I assume that these have safety factors built into them and allows for people of all ages...like 'The Snake':P

I'm more interested in driver reaction to green lights, I assume it's a lot faster (people such as myself can pre-empt the green light) especially at busier intersection.

Thanks,
Paul

Timinau (Civil/Environmental) · Answer 4 · 2012-03-20 00:32:05

Hi Paul,

There was a paper written by Akçelik and Biggs (from 1987), which referenced a great deal of information on studies to do with the acceleration of vehicles at intersections. Unfortunately I cannot remember what it was titled., but I'm sure Google will find it for you.

I hope that helps.

Tim Absalom
Altus Traffic
Australia

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Traffic signals and driver reaction time