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Tuesday, 21 November, 2000, 10:42 GMT
Congestion comes in waves - so surf!
London's orbital motorway
Go slow: Variable speed signs on the M25
Jumping lanes won't get you there any faster, nor will driving bumper-to-bumper. Instead, an amateur traffic boffin likens jams to ocean waves in a bid to beat congestion, writes BBC News Online's Megan Lane.

Frustrated British motorists are logging onto an American website to find novel ways to avoid traffic jams.

William Beaty, an electrical engineer from Seattle who runs the science hobbyist website, has received numerous e-mails from UK drivers fed up with crawling along crowded motorways at a snail's pace.

M4 motorway
A typical Bank Holiday pastime
His theory is that traffic jams behave much like waves which "swamp" approaching drivers.

The way to calm the waters is to break the flow of traffic heading into the dams of congestion, he told BBC News Online.

Instead of stopping and starting - the typical driving pattern in a jam - try to stick to the average speed of the traffic, he says.

Click here to see the wave effect of a car accident

Although this means a gap will open up as the drivers in front race ahead, this space will close as they then grind to a halt.

Time it right, and your car will arrive at the next "stop wave" just as they are pulling away again.

While testing this theory in rush hour traffic, Mr Beaty noticed that although drivers in adjacent lanes continued to ride their brakes, those behind him were forced to drive at a steady 35mph.

"My single tiny car had erased miles and miles of stop-and-go traffic."

Top tips

But the best way to beat congestion is to be a public-spirited driver, Mr Beaty says.

  • Before you arrive at a jam, slow down to create a large space in front of your car

  • Let other drivers merge ahead of you, instead of blocking "cheaters" who try to get ahead - cutting them off can trigger traffic jams

  • Try to drive without hitting the brakes on busy motorways - you will need to let a large space ahead of you grow and shrink.

Round and round

In the UK, a segment of the M25, London's orbital motorway, is used to road test technology to improve traffic flow.

The motorway and connecting roads are monitored via video cameras, and speed limits can be lowered in busy periods and around accidents.

"The signs also say where the jam is. It largely works," a Hampshire-based motorist wrote in one e-mail to Mr Beaty.

Trucks blocking a motorway
Let a gap open up in front
Although variable speed limits can ease congestion, many drivers ignore the signs because they don't know their purpose, Mr Beaty says.

"And when police come down hard on violators, or cameras are installed to catch speeders, people assume that the government is motivated by trying to make money from fines."

Instead of trying to change the driving habits of a lifetime, the government should instead aim to educate commuters by posting "traffic jam elimination speed" on the signs, he says.

Another option is to install road signs advising drivers that exceeding the speed limit can cause traffic jams, a move which could turn public opinion against speeders.

"In bad traffic conditions, peer pressure becomes enormous. In other words, harness public opinion rather than trying to fight it."


Another phenomenon that fascinates Mr Beaty is the tailback that persists after an accident.

Even if the wreck has been removed, backed-up cars remain at a standstill.

crash test dummy
"Move along, nothing to see here"
This is because each driver waits for the car ahead to pull away before hitting the accelerator, he says.

Thus each following driver remains stalled for a moment longer than the preceding driver - a delay which is further exacerbated by "rubberneckers" who slow down to peer at the aftermath of the crash.

The jam "evaporates" in a wave which sweeps back from the site of the accident, and more cars stack up at the end of the jam.

One of the e-mails recounts a solution encountered on the M1, the UK's main north-south motorway.

"I got stuck behind a police car doing about 40mph - the limit is 70. After about 20 minutes, he pulled off and let everyone go.

"Just after this, I passed the scene of a recent accident and almost immediately joined the back of a flow of traffic doing about 65mph."

By slowing the drivers approaching the scene of the crash, the police officer ensured that the stationary traffic in front had time to clear.

So it would seem that the trick to beating traffic jams boils down to one simple rule - slow down to go faster.

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