Polite drivers cause traffic jams, says new research

Motorists who are too polite or timid in their driving style are the cause of lengthy traffic jams where roadworks are underway, a scientist has said.

People are reluctant to use empty lanes where lane closures are approaching so they merge early, which doesn’t help traffic flow and wastes very expensive stretches of road, says Dr Guy Walker, Associate Professor in Human Factors with Heriot-Watt’s Institute for Infrastructure and Environment in the UK.

People are self-conscious, if everyone else is merging early you become extremely reluctant to do something different– Guy Walker, Heriot-Watt University

In a search for novel solutions to traffic jams, Walker has been working with the Scottish Road Research Board and traffic simulation company SIAS Transport Planners, and he has concluded that big traffic problems are caused by the small actions of individual drivers.

"No one wants to be seen by fellow drivers as the type of person who pushes in," he said. "This behaviour, however, leads to the loss of a further lane of capacity, that’s in addition to the ones already closed because of roadworks."

This is a waste, Walker says, because it costs about $50m (£30m) to build a mile of motorway and about £40,000 per year to maintain it, so drivers’ reluctance to be pushy means that this expensive resource is not being used.

"People are self-conscious," Walker says. "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 is telling you to. Behaviours like these are contagious, which is why people merge into the inside lane earlier and earlier, making congestion, anxiety and frustration worse."

To reduce the amount of time spent queuing and in turn reduce the stress levels of drivers, Dr Walker suggests simple solutions taken from an unlikely source, the amusement industry, which has grappled with the psychology of queueing.

At theme parks, popular rides have signs estimating the wait time. If people get through the queue faster than the estimate, their emotional response is not anger at having had to wait so long, but rather happiness at having cheated the inconvenience a little.

"Research shows people who arrive at the front of a queue more quickly than expected are the happiest of all," Walker said. "There are lots of clever ways we can help to reduce drivers’ anxiety while queueing and make waiting times seem shorter than they really are. Instead of signs saying ‘stay in lane ‘what about ‘drivers ahead don’t mind you pushing in’?"

He added: "If drivers aren’t using this expensive resource because we object to pushing-in, then we have a problem. The good news is that we don’t necessarily need lots of big expensive engineering to regain the lost lane of capacity. Instead we can use small, clever and highly cost-effective solutions."

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  1. Great, but sending timid drivers to Nairobi, Lagos, Johannesburg, Bangkok, Jakarta, Manila or many other mega cities in so called developing countries, where the use or precious road space was clearly understood ages ago, would be more educational.

  2. Yet another so-called Scientist interfering in something he knows nothing about, from years of motoring and also working in Civil Engineering alongside Traffic Management companies it is the exact opposite of what this guy is suggesting.

    To be able to bring some science into this so the silly scientist can understand, think of it as sand passing through an egg timer, if each grain merged early and went through single file (impossible I know but bear with the analogy) it would pass through quickly, if two grains try to pass similtaneously they impede each others progress.

    I sincerely hope this guys research is not funded by the Tax payer. He should get back to his bunsen burner and do some proper science.

  3. What a strange finding, and one which runs contrary to any experience I have had!

    The use of two lanes until the bitter end is usually dominated by drivers who just want to overtake everyone else who is displaying road courtesy by waiting patiently. Then, whenever it is a last-minute merge caused either by inconsiderate drivers, or simply because the road layout confuses people, there is a horrible delay while cars try to merge in the limited space.

    Sorry, but I think academia has it wrong and I bless the wagon drivers who agree with me – the ones who pull out into the outside lane to stop the cowboys overtaking and causing jams!

  4. Comment: Experience on the M8 reinforces this message; ‘Lane Closed’ and ‘Merge Right’ messages at least 2 miles back from a lane-blocking incident left two of three lanes empty over many hundred metres and increased frustration as the those few ‘pushing-in’ and/or taking advantage of a exit slip lane advanced faster. There is a fine balance and a moving target to be achieved in giving drivers sufficient warning of obstructions on the one hand and not creating your ’empty lane’ scanario on the other. However if we accepted the concept of zippering up and positively encouraged people to use all lanes right up to an obstruction, then your model would work. Take away the identity of the lane(s) closed and simply advise of ‘obstruction ahead’ or ‘be prepared to stop’ to limit preferential lane switching and the flow model starts to look achievable.

  5. Signs saying ” queue in both lanes and merge at the roadworks” would be much more helpful in reducing the queue time followed with a cog icon and the words merge now just as the lane reduces . I have observed this problem for many years and acted appropriately to keep the queues I am in to a minimum.

  6. Though I have great respect for Heriot Watt University (my son and Partner studied there as a Building Surveyor), I really don’t think it needed a Uni research project to make this conclusion. It is stark staringly obvious and I have been advocating for years.

    Another area causing delays and queues at road works and most traffic lights, is the gaps drivers carelessly leave between each vehicle passing over ‘the line’. Every wasted car length between cars is another vehicle left at the rear of the queue. It is not uncommon to see 3 or 4 (or more) car lengths between vehicles passing the lights. At 5mph this is not necessary on braking grounds. What is the cause – ignorance, lack of awareness, arrogance (it’s ok I’m through!), timidity, just not paying attention – or all of the above! Again this isn’t rocket science. Anyone remember policemen on duty at such situations in emergencies? What did they do – vigorously waive cars through encouraging speeding up and closing gaps – simplesx!

  7. If more drivers were polite and considerate there would be much less road rage and accidents.
    Roadworks are only one cause of traffic jams which are caused by too many cars on the roads causing greater congestion and pollution especially in urban areas.
    Planners should consider the increase in traffic generated when approving additional residential, commercial and industrial developments which brings with it additional infrastructure requirements to the region as well as damage to the environment.

  8. To be fair, approaching lane closures/obstructions on many motorways, one now often sees signage saying “Use both lanes” or similar. The concept is not new.

  9. This does not reduce queuing time, it would sensibly manage expectation and reduce frustration. The lorry drivers who ride both lane need some salt on their ‘Yorky’ they don’t own the road, they simply keep motorway maintenance companies in business. If everyone follows the signs, it would reduce frustration, time markers would be a great incentive, and make driving a more controlled activity. Being polite is a dying habit, it should be positively encouraged. I think a bit of positive spin would make more sense.

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