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.