Research by a leading Scots scientist found traffic jams, especially when drivers are faced with roadworks or lane closures, can be up to 20 per cent worse than engineers expect due to drivers being overly polite on the highway.
Dr Guy Walker, associate professor in human factors with Heriot-Watt University's Institute for Infrastructure and Environment, conducted research into drivers' behaviour to find new solutions to an old problem.
Major traffic delays are caused by small actions from individual drivers, according to the research by Mr Walker.
He said: "My research found that the majority of drivers, when confronted with roadworks ahead, quickly move into the nearside lane as early as possible rather than merge at the forefront of the queue. No-one wants to be seen by fellow drivers as the type of person who pushes in.
"This behaviour however leads to the loss of a further lane of capacity, in addition to the ones already closed because of roadworks."
He added: "People are self-conscious, if everyone else is merging early you become extremely reluctant to do something different, even if a big sign at the side of the road.
"Behaviours like these are contagious, which is why people merge into the inside lane earlier, making anxiety and frustration worse."