Overly polite drivers, not roadworks, cause traffic jams

August 25, 2014, Heriot-Watt University

British motorists who are too polite or timid in their driving style are the cause of lengthy traffic jams across the UK, particularly when faced with roadworks or lane closures, according to a leading Heriot-Watt research scientist who found traffic jams can be up to 20 per cent worse than engineers plan for, due to drivers being overly polite on the road.

Dr Guy Walker, Associate Professor in Human Factors with Heriot-Watt's Institute for Infrastructure and Environment, has been working with the Scottish Road Research Board and SIAS Transport Planners Ltd, the UK's foremost traffic microsimulation company, carrying out complex research into driver behaviour to find novel and innovative solutions to major . He says that big traffic problems are caused by small actions from individual .

"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, that's in addition to the ones already closed because of roadworks."

It costs about £30 million to build a mile of motorway and about £40,000 per year to maintain it, but driver's reluctance to push in means this expensive resource is not being used.

Dr Walker addes, "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 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."

Simple solutions

To reduce the amount of time spent queuing and in turn reduce the stress levels of drivers, Dr Walker suggests simple yet novel solutions taken from an unlikely source, the amusement industry. The psychology of queueing is used to good effect here, and the same ideas could make drastic positive changes to the road network as well.

He said, "One extreme solution is to build more lanes. Unfortunately, it costs millions to build a mile of motorway, and even more to maintain it, and 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."

Dr Walker suggests adopting some of the techniques used at theme parks. One example is where popular rides provide an estimated wait time when a person joins a queue. If they arrive at the front of the queue quicker than the time they were given, they are less likely to become angry at the amount of time spent waiting, according to Dr Walker.

"In fact, research shows people who arrive at the front of a queue more quickly than expected are the happiest of all. There are lots of clever ways we can help to reduce driver's 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'?"

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5 / 5 (4) Aug 25, 2014
No one wants to be seen by fellow drivers as the type of person who pushes in.

Rather, everyone wants to merge early because they don't want to get stuck at the end of the closed lane.

The zipper effect doesn't really work at low speeds and high traffic because people can't see that well behind them to the lane they're merging into, and more cars are merging all the time so the gaps get smaller, and people are being dicks and driving bumper to bumper anyways, so the further down the road you go the more difficult and awkward it becomes to find a gap and fit yourself into it.

The earlier you manage to merge, the less hassle it is. It has nothing to do with being polite.
5 / 5 (2) Aug 25, 2014
The simpler solution is to force merges to ALTERNATE. Don't let one lane be the primary and one be the secondary, that causes this exact scenario. Have the lanes like a 'Y' and a sign that says alternate merge. If it's an extended merge for days or weeks, they could install a simple traffic flow light for left lane then right lane, just like traffic merge lights onto highway.

This would also reduce anger with people as no one lane is the "King" so everyone has to play nice.
4.3 / 5 (3) Aug 25, 2014
They aren't very polite when you get to the very end of the closed lane and they won't let you in.
not rated yet Aug 25, 2014
Ziper effect works well - it just takes a while for people to get used to it. I remembre that a decade ago in germany we had the exact same issue described in the article. Somehow the information was spread about merging as late as possible and now it works fine wherever you look - without people becoming aggressive because they see you as cutting in at the front

(In the end: you're maybe 5 cars ahead in slow moving traffic. You're not suddenly gaining hours (or even minutes) of travel time over thoe behind you...so why get agitated?)
5 / 5 (2) Aug 25, 2014
You have to judge when is the longest you can wait and still be assured that you are able to smoothly merge. If you wait till the last moment you cause just as much backup as if you merged too early.
not rated yet Aug 26, 2014
People aren't being overly polite, they are avoiding the real problem of the traffic getting more dense ahead and so getting stuck in the right lane and not being able to merge left safely. It is a better strategy to merge left early. Equally, if there is a slow truck ahead it is better to merge right early so you don't get blocked in if traffic increases when you get close behind the truck.

These behaviours don't cause traffic jams, they only remove a few 100m of one lane, which will be blocked anyway.
Whydening Gyre
not rated yet Aug 26, 2014
No one wants to be seen by fellow drivers as the type of person who pushes in.

That doesn't seem to be an issue for many Chicago drivers...

The earlier you manage to merge, the less hassle it is. It has nothing to do with being polite.

And that is just the simple common sense of it... So - be polite and let others merge in early...:-)
not rated yet Aug 26, 2014
Being too civil is a problem? Has medication been considered? Ethanol, for example, helps remove pesky inhibitions.

I note that British drivers score abysmally low in road fatalities - among the lowest in the world, per capita something like a third that of the United States.
not rated yet Aug 26, 2014
If you wait till the last moment you cause just as much backup as if you merged too early.

Currently the official recommendation is to drive to the head of the lane and then merge (at least in germany).

On an unrelated note: It seems that the amount of road rage has significantly diminished over the years. The Autobahn used to be called "germany's largest, open psychiatric ward". But it's been quite some time since I saw someone aggressively using turn signals or headlights (or just simply humping your trunk) to get ahead.
5 / 5 (1) Aug 26, 2014
Ziper effect works well - it just takes a while for people to get used to it.

It works when the road throughput is sufficient and the lanes are rolling normally.

It doesn't work when you have lane closures and there's a bottleneck in the road that would normally carry many times the amount of traffic that will fit through the gap. In those situations the traffic becomes bumper-to-bumper anyhow and merging becomes difficult.

The "theoretical" idea seems to be that people would behave in an orderly zipper line fashion and maintain speed even when you've got inches between cars, but that's not what really happens. People get to the end of the lane and then they simply can't get in because the traffic is too dense, so they merge early where there's still enough of a practical "safety margin", and the early mergers act to increase the flow resistance of the bottleneck as if a longer section of the road was closed.

5 / 5 (1) Aug 30, 2014
The comment about 'alternate' (Verb) is *almost* there.

You also need strict 'No Overtaking Beyond This Point' to make the 'Merge By Turn' work fairly.

FWIW, have they addressed the brain-glitch that afflicts some drivers when they *finally* notice an ambulance or fire-truck --Both large, bright & loud !!-- behind them ??

About 80% of drivers will shift *in unison* to one side or another over a significant stretch of road to provide a path. The remainder, bizarrely, will do the opposite, which grid-locks the others' gap...

1 / 5 (1) Aug 30, 2014
Politeness - another problem to be solved by self-driving vehicles.

Ever follow someone who stops abruptly to let someone out of a parking lot because it's 'polite'?
Aug 30, 2014
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3 / 5 (2) Aug 30, 2014
The traffics at the Asian streets only rarely jams, because it runs in stochastic mode, dual to organized Western one. The drivers there aren't extraordinarily polite and they only rarely slow-down, but they're always prepared to change the direction. It https://www.youtu...zj7WyzE, until your behavior remains predictable.
Maybe you've never been there.
Aug 31, 2014
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