Police forces have clarified the correct way to merge lanes when two lanes converge into one on UK roads, a situation nearly every British driver will recognise. Using the right-hand lane to pass queuing traffic and merge at the last moment is endorsed as proper practice, while deliberately blocking another vehicle can lead to a £100 fine and three penalty points.
What is zip-merging?
The recommended technique when two lanes merge into one at a designated point is known as "zip-merging". Rather than moving into a single lane immediately after seeing advance warning signs of a lane closure, drivers should take turns merging at the actual point where the lane ends. The name comes from the way the manoeuvre resembles a zipper's teeth interlocking, and it is believed to ease traffic flow substantially.
Police forces, the Highway Code, the RAC and National Highways all endorse this approach. Avon and Somerset Police explained 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."
Official guidance on merging
National Highways offered comparable guidance, stating: "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, 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."
The RAC supports this approach, explaining: "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 motoring organisation adds: "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."
Penalties for improper merging
While drivers will not face a fine for joining the left-hand queue early, or for using the empty lane up to the merge point, improper use of merger lanes can lead to a driving conviction, penalty and points. Attempting to block someone from using the less congested lane to overtake stationary traffic could result in prosecution for careless driving, or potentially something more serious. The fixed penalty for careless driving now stands at £100 alongside three 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." Drivers who are blocked by someone who does not understand proper merge use are advised to avoid responding with aggression. If they have a dashcam, footage can be submitted to Operation Snap, a UK police scheme enabling the public to upload video evidence of suspected driving offences.
