Tracking data shows M25 the UK’s slowest motorway, surprising no one
The M25 has the slowest average speed of any UK motorway, according to an in-depth analysis of British traffic.
It’ll come as no surprise to anyone who uses it frequently, but the average speed on London’s orbital motorway is just over 25mph. That means it takes an average of five hours to circumnavigate the capital over the entire 117-mile route.
The next slowest is the M4, another motorway notorious for delays. The average speed here, however, is more than 30mph – a significant improvement over the M25. But the third slowest is the M606, which boasts a positively meteoric 41.7mph.
These findings come from tracking firm Satrak, which used data from over half a million vehicles gathered over the year 2016. The data covers Britain’s entire 2,173 miles of motorway network.
It’s not all doom and gloom, though. The 10-mile M57’s average speed is just under 64mph, which is just 6mph below the speed limit. The M18, which runs for around 26 miles, has an average speed of nearly 63mph, while cars on the M40 have a mean speed of more than 62mph – the highest in southern England.