Drivers in London are constantly caught up in traffic jams and many are torn between whether to make a last-minute merging-in turns or not when the lanes change

Motorists who dare to take the right lane in a situation where two lanes merge into one are often met by angry stares from other drivers as they drive on.

But in fact when it comes to zip merging, as it is known, the Highway Code says it is safe, sensible and recommended to do so and it is NOT pushing in.

The theory is that people who choose to drive straight ahead on the right lane before merging in actually keep the flow of of slow traffic moving.

But drivers stuck in the left hand lane are often unaware of this and instead tend to speed up and block entry for any cars attempting to move in from the right hand lane as they see it as jumping the queue - this is in fact wrong.

The RAC also argues that those who choose to move into an empty right hand lane before the two lanes merge into one are actually doing the right thing.

'Merge in turn' symbols on the roads

What do they say?

A study conducted in 2008 by Ken Johnson, a state work zone engineer in Minnesota, lays the foundation of the argument.

The results claim that zip-merging REDUCES crashes, speeding and congestion.

The study found three primary benefits of using zip-merging. They are:

  • A reduction in the difference in speeds between the two lanes: without the urgency to move over, the traffic is travelling at roughly the same speed in both lanes, making the merge easier and safer.
  • The length of queue is reduced by up to 50%, which is critical in areas where you find junctions and slip roads.
  • When nobody has a perceived advantage, the potential for "road rage" is reduced significantly.

What does the Highway code say?

The Highway Code also backs the practice of zip merging, although it does recommend caution.

Rule 134 states: “You should follow the signs and road markings and get into the lane as directed.

"In congested road conditions do not change lanes unnecessarily.

"Merging in turn is recommended but only if safe and appropriate when vehicles are travelling at a very low speed, e.g. when approaching road works or a road traffic incident.

"It is not recommended at high speed.”

'Merge in turn' symbols on the roads

What is zip merging?

During a lane closure on a motorway or dual carriageway a majority of motorists will follow the conventional method of moving early to the left hand lane, creating one long, slow traffic queue and an almost empty outside lane.

While drivers on the inside lane think they are in the right and will tut or make an angry gesture at anyone who uses the right lane, it is said to be more beneficial for traffic flow to use the open lane until the last minute.

This ensures the length of both lanes are fully utilised and motorists only merge in at the point at which the road narrows to a single lane.

While many people sitting in stationary traffic get annoyed as they watch other motorists drive by, maybe it's time to remove old-fashioned British queuing from the equation and use both lanes until the last minute.

Therefore, if all cars use all the space available to them on both lanes then congestion should reduce.

Can more be done to help motorists in London?

Ashley Behan, national observer at IAM RoadSmart believes more can be done so that unsure drivers are clear on the rules.

He said: "The use of zip merging is useful in reducing congestion, and this has recently been acknowledged by Lincolnshire County Council .

“This is evident by the placing of a sign on Canwick Hill so that now as you head into the tidal flow it directs you what lanes you can use.

"What is needed is more use of clear ‘merge in turn’ signposting so that all drivers know what is expected of them."

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