Police and the Highway Code have confirmed that the correct technique for merging when two lanes converge into one on UK roads is known as "zip-merging". Rather than pulling into a single lane as soon as a lane closure is signposted, drivers should take turns merging one at a time at the actual point of closure. The method is called zip-merging because it resembles the teeth of a zip fastener coming together, and it is widely regarded as significantly reducing traffic build-up.
What the police and Highway Code say
The police, Highway Code, RAC and National Highways all agree on this approach. Avon and Somerset Police stated that the technique "helps make full use of the available road space" and noted: "Problems tend to arise when drivers are unwilling to allow others to safely merge, or when motorists change lanes aggressively, without adequate observation, signalling or consideration for other road users."
National Highways offered similar guidance, commenting: "By keeping both lanes in use until the merge point, congestion is minimised and journey reliability is improved."
Highway Code rule 134 covers lane-merging by stating: "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."
Why merging early creates problems
The RAC agreed, stating: "When motorists encounter a lane closure on a motorway or dual carriageway, the majority of drivers follow the etiquette of moving over early, but this creates one long, slow line of traffic and a near-empty outside lane."
The RAC added: "While motorists on the inside lane might think they're doing the right thing, it can be more beneficial to continue using the open lane until the last minute, utilising all of the available road and then 'merging in turn' at the point at which the road narrows to a single lane."
However, many drivers find it annoying to watch fellow motorists using the outside lane while they sit stationary on the inside. The RAC noted: "But if we remove good old-fashioned British queuing etiquette from the equation taking all emotion out of the scenario, the plain and simple fact is that two lanes of slow moving traffic are better than one. So if cars use all of the space available to them on both lanes, it should result in the line of congestion disappearing, or at the very least reducing."
Penalties for incorrect merging
While there is no penalty for joining the left-hand queue prematurely, or for using the vacant lane right up to the merge point, improper use of merger lanes could lead to a driving conviction, fine and penalty points. For example, attempting to block someone using the less congested lane to overtake queuing traffic could result in prosecution for careless driving, or more serious charges. The fixed penalty for careless driving is now £100 with 3 points on the driver's licence.
National Highways stated: "Dangerous, careless or inconsiderate driving can occur if a driver forces their way into traffic, deliberately obstructs other vehicles, or carries out manoeuvres which create a risk of collision."
Should drivers encounter obstruction from someone who does not understand the proper method for using lane mergers, they are advised to avoid responding with anger. If they have a dashcam, they can submit the footage to Operation Snap, a UK police initiative that allows members of the public to upload video evidence of suspected driving offences.
