Lane discipline at the end of a two-lane road often devolves into chaos. Drivers encounter signs instructing them to merge in turn, yet anecdotal evidence suggests many ignore these requests. Observations of roadways reveal that some drivers force a line of traffic behind a lorry while leaving the cab’s lane empty. Others maintain a single queue while the adjacent lane remains vacant, save for litter and empty coffee cups.
The logic behind the zipper method
The zipper merge originated in the United States as a traffic flow measure to ease congestion when a road narrows. The method directs drivers to wait until the lane closure point before changing lanes. A 2008 study by state work zone engineer Ken Johnson found that this approach reduces queue length by up to 50 percent. Johnson argued that equal disadvantage for all drivers lowers the risk of road rage.
Despite the data, motorists often criticize drivers who merge late. One writer noted that social media frequently associates this behavior with Audi vehicles. Critics claim such drivers display a lack of courtesy. However, critics may be overlooking the official guidance found in the Highway Code.
Official guidance vs. practice
Rule 134 of the Highway Code under the section Lane discipline advises drivers to follow signs and markings. The code states that merging in turn is recommended only when vehicles travel at a very low speed, such as near roadworks or incidents. It explicitly notes that this method is not recommended at high speeds.
Drivers who form a single queue early may believe they are being polite. They might also believe they are following the spirit of British queueing culture. The Highway Code, however, prioritizes safety and flow. Drivers waiting in a single line while another lane sits empty can create a bottleneck. The zipper method attempts to balance the flow of traffic more evenly across both lanes.
Not to mention missing the first 20 minutes of Pointless.
