Complete the gaps in the following summary by using NO MORE THAN THREE WORDS taken from the passage.
Deadly Illusion Brings Death on the Road
Children are being killed on Britain’s roads because of an optical illusion, warn researchers at the University of Aberdeen. The illusion fools drivers into underestimating how long it will take them to stop, and by the time they discover their mistake it is too late to avoid an accident
About 50 children are injured on Britain’s roads every day. Investigators looking at this problem have tended to blame children’s inexperience and carelessness. But the researchers at Aberdeen suggest that the problem lies with the drivers. Doug Stewart of the university’s engineering department says that the optical illusion is responsible for more than half the injuries to children on the roads.
People normally judge the time it will take an approaching object to reach them by the rate at which its size increases, a phenomenon called optic flow. This is adequate for catching a ball or ducking a projectile, Stewart says, but for car drivers it is only effective in the final second or so before collision. At speeds of 50 kilometres an hour, which are typical for traffic in towns, it takes around 3 seconds to stop a car.
Stewart and his colleagues Chris Cudworth and Rely Lishman say that instead drivers judge the time before a collision by subconsciously measuring the angle between the top and the bottom of the pedestrian’s image. In the absence of any other clue, they assume that the pedestrian is an adult and judge the distance accordingly.
If the pedestrian turns out to be a child, this assumption can be lethal, as it leads drivers to believe the child is farther away than it really is. By the time the error has become apparent it can be too late for the driver to avoid hitting the child.
Stewart and his colleagues conducted a series of tests in which volunteers acted as drivers in a computer simulation of a car approaching a pedestrian. In the test, volunteers were presented with a child one metre tall and an adult 1.8 metres tall. The volunteer "drivers” were asked to stop at a safe distance in front of the pedestrian.
Describing their results in the journal Perception, the researchers say that drivers were more likely to make errors when the image was a child’s. They also found that the driver’s height above the road influenced the number of errors. A driver sitting 1.8 metres above the road was less likely to misjudge the distance than one sitting one metre above the road.
This seems to be borne out by the road accident statistics. Cars are two to three times more likely than lorries to hit children, when the number of each type of vehicle on the road is taken into account. Lorry drivers sit higher up than car drivers.
Stewart says that the risk of drivers making potentially fatal errors can be reduced by providing visual cues for drivers about the size of the object they are approaching. Britain has one of the worst child safety records in Europe. One reason, says Stewart, is that other European countries have more zebra crossings, and that the markings on the road help drivers to distinguish between a child and an adult.
Britain's zebra crossings are gradually being replaced by pelican crossings, which have traffic lights but no striped markings on the road. Stewart says that pelican crossings should also have road markings to help drivers judge the size of a pedestrian.
In correspondence with Stewart, the Department of Transport describes the research as “interesting”, though it does not accept that the paper “demonstrates that perceptual error in the way described is the main reason for children having a much higher accident rate”. The DoT does agree, however, that marking the road with stripes at pelican crossings could improve things. Unfortunately, says Stewart, there is no indication that the positive tone of some of the DoT’s comments has led to “action to curb child pedestrian accidents or to promote further research”.
British researchers have evidence to believe that the number of children by cars while crossing roads is related to drivers' inability to judge how for they are from young pedestrians. Stewart of the University of Aberdeen believes that drivers assume that pedestrians crossing roads are adults and when it is crossing the road, they tend to think that the child is than he really is. Because of this misperception of distance, drivers are not able to stop their cars in time to prevent a . Britain’s child are worse than those in many other European countries. This, according to Stewart, is because many crossings in Britain do not have that help drivers to tell if the in front is a child or an adult. In Britain, have lights but there are no markings on the road. Stewart thinks that markings should be painted.