Could longer on amber reduce collisions?

12.00 | 8 March 2016 | | 8 comments

Increasing the length of time traffic lights are on amber by just 0.5 of a second has the potential to improve road safety, according to research from a Dutch transport consultancy*.

The research, conducted by Goudappel Coffeng, found that slightly increasing the duration of the amber light led to a 50% reduction in the number of motorists going through red lights.

The research suggests that amber lights are something of a grey area, with many drivers unaware of the length of time traffic lights remain on amber. This ‘confusion’ creates a two-factor challenge for drivers – the need to pass through the lights, and the ability to do so safely.

The study suggests that giving drivers more time to make a split-second decision means they are more likely to make the safe one.

Another problem highlighted is the variation in the length of time required for different road users to safely navigate traffic lights. For example, a two-second amber light is sufficient for cyclists to cross safely, while a car travelling at 80kph (50mph) needs around five seconds to safely come to a halt.

The study found that where amber periods are too short, many drivers believe they have the ability to get past the traffic lights safely, when in fact they often find themselves skipping the red light.

The research also acknowledges that increasing the amber period too far can have an adverse effect on safety, causing unnecessary periods of uncertainty.

Luc Princes, lead researcher, said: “If we look at countries in Europe and North America, we see a uniform yellow (amber) time, varying within a range of up to one second.

“That one second does not sound much but it is. Our research shows that a large part of the decision to drive through a red light happens in the first half second.”

According to a Dutch newspaper report on the study, the changes recommended in the report have now been incorporated into official recommendations about how best to set traffic lights to local conditions, and were put into effect in Holland in February 2016.

*The Goudappel Coffeng report is written in Dutch. Some of the wording in this news report has been adjusted for translation purposes.

Photo: Yenan Zhu via Flickr. Use under creative commons.


Comment on this story

Leave a Reply

Your email address will not be published. Required fields are marked *

Report a reader comment

Order by Latest first | Oldest first | Highest rated | Lowest rated

    Just briefly running on from R.Craven’s comment. In my experience, and what I have taught others is that on the approach to lights at green you need to decide a point of commitment – a go, no-go point. Before that it is necessary to sort out speed and gear (and obviously position if there is more than one lane). The POC would be so that you could smoothly come to a standstill if the lights change to amber at or before that point. After that you are committed if there is no obstruction at the junction. Getting PSG sorted before the POC means you can concentrate whole heartedly on the lights in case they should change.

    Nigel ALBRIGHT
    Agree (0) | Disagree (0)

    One very useful addition to traffic lights, for vehicles and pedestrians, is a countdown. So a vehicle is shown how many seconds to the amber/red light and then again showing how long to the green light. They certainly have this in parts of China and I think Turkey as well, as well as other countries probably. It takes away all the uncertainty allowing vehicles especially to judge their approach. Cost would be horrendous for the whole of the UK but it would be great to see it trialled on a large scale to monitor the effects.

    Mike, Leicestershire
    Agree (0) | Disagree (0)

    As Nick says, amber is a stop lamp. That also applies when going to green. It is probably not necessary to increase the time on amber by 0.5 secs and all that that involves across the country. You just need to nail those who go over the line before the green. If they are short of funds that should sort it out.

    Nigel Albright
    Agree (0) | Disagree (0)

    Interesting research. From my experience of working within road safety on international projects, it’s not always possible to apply overseas research to the UK context. Road user culture can vary significantly from country to country and this should also be taken into consideration.

    Nadeem Mohammed
    Agree (0) | Disagree (0)

    I remember what I thought was a good idea from Germany years ago – if a vehicle approached the traffic lights in excess of the speed limit, they changed to red. Obviously speed detection would be an appropriate distance from the lights for braking/stopping.

    Paul Biggs, Staffordshire
    Agree (0) | Disagree (0)

    I was told in my driving lessons that amber meant stop if it is safe to do so. i.e. do not slam on your brakes so that the person behind crashes into the back of you. (granted they should be a safe distance behind you anyway!) If Vehicle A travels over the stop line during the amber phase the danger will come if Vehicle B – the first vehicle in the next phase to receive a green – can move into the junction before Vehicle A has cleared the junction. Isn’t that why there is usually an all red stage?

    My reasoning and experience tells me that drivers would quickly learn that the amber was staying on longer and so would happily travel through the stop line longer after the amber appears than previously as they know they are “kept safe” by the all red stage? Obviously some humans will still drive through red signals either deliberately or negligently and hit a legally compliant driver’s vehicle as once happened to me.

    Nick, Lancashire
    Agree (0) | Disagree (0)

    R Craven of Blackpool… You’re incorrect to say Amber shows for 2 seconds between green and red. In the UK, all ATS already show Amber for 3 seconds before red.

    It is Red & Amber together which show for 2 seconds before green.

    Lee Davies
    Agree (0) | Disagree (0)

    The default setting for amber lights going from green to red is 2 seconds and that equals the distance that a vehicle travels at 30 mph as 90ft, (braking distance as shown as 75ft in S.126 HC) give or take a foot or two. The problem is that drivers are unaware that they are required to stop actually on the amber lights (HC page 102) and many just see it wrongly as a hurry up and actually speed up when approaching. I would therefore think that if time is increased to say 3 seconds it may have the effect of allowing vehicles to stop as they should do but for some it will mean that they have more time to evade the red light. If the timing is changed then drivers, not being informed, would not recognise any change and continue through the lights as before so no change. Perhaps it would help if drivers were re educated that AMBER MEANS STOP and not just come to a rest before the red light.

    R.Craven Blackpool
    Agree (1) | Disagree (0)

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.