25 July 2001: The UK Institute of Advanced Motorists (IAM) has suggested 'zip merging' as a more efficient system of dealing with lane closures on dual carriageways and motorways.

'Zip merging' means all available lanes are used right up to the bottleneck, with vehicles then merging in turn, one from the left, one from the right, in the style of a zip.  The idea features in the summer edition of the IAM members' magazine, Advanced Driving and draws attention to a lack of advice on this point in the Highway Code.

"Three-into-two and two-into-one lane merge situations are very common on our roads and clear advice in the Highway Code on how to deal with them is essential." says IAM Chief Examiner Bryan Lunn. Should you get into the queue and crawl for perhaps a mile or more, even though there is a totally empty lane adjacent to yours going right up to the start of the blocked lane?  Or should you use the empty lane right up to where the lane closure begins and then blend in with the traffic in that lane?

"In our view, the sensible advice for all lane merging situations is that drivers should reduce their speed and increase the gap between themselves and the vehicle in front. All available lanes should be used right up to where the lane closure begins and vehicles should merge in turn - one from the left, one from the right, and so on."

Mr Lunn suggested that if everyone did this, the traffic will continue to flow at the point where lanes are closed or blocked, and everyone would get past the obstruction quicker.  All available road space would be used efficiently, and the 'absurd situation' of long queues of traffic alongside a totally empty lane will be avoided. 

"Zip merging or 'interleaving' works very well in other countries, where explanatory road signs have diagrams showing how vehicles should merge in turn from two lanes. Some drivers seem to think that vehicles merging from a blocked or closed lane are jumping the queue.  This brings out the 'I'm first, you're next' attitude in them, which affects safety and adds to the congestion and frustration levels. Some lorry drivers deliberately straddle the two lanes, thus preventing car drivers from using the empty lane - an unhelpful and stupid manoeuvre," Mr Lunn said. 

The zip merge' proposal will now go forward to the UK Highways Agency.