By Transport Correspondent | 4 April 2025
London’s buses are moving at their slowest pace in over a decade, with average speeds hitting record lows. Transport for London (TfL) has long promised to tackle the issue, but despite various initiatives, meaningful progress remains elusive.
The core problem is obvious: buses are stuck in traffic. But a little-known rule about road congestion suggests that TfL’s latest attempt to fix the issue is doomed to fail.
The ‘induced traffic’ effect
One of the fundamental principles of traffic management is that increasing road capacity does not necessarily reduce congestion. Instead, it often leads to a phenomenon known as “induced traffic.” When more road space is created—whether by adding new lanes or tweaking traffic signals—more vehicles use the space, eventually restoring congestion to its previous level.
Studies have consistently shown that any measure designed to “smooth traffic flow” tends to attract more vehicles onto the roads, negating any short-term improvements.
TfL’s latest solution—adjusting thousands of traffic light settings across the capital—is based on the flawed assumption that allowing more vehicles to pass through a green light will lead to lasting benefits for bus speeds. While this might provide a brief improvement, in the long run, induced traffic will mean congestion levels return to where they were before.
Why this won’t work for buses
Unlike cars, buses do not simply share space with other vehicles—they are heavily dependent on dedicated infrastructure and traffic management policies that prioritise their movement. However, at most junctions, buses remain stuck in general traffic.
By adjusting traffic signals to increase the flow of all vehicles, TfL risks undermining its own efforts. If more cars and vans are able to pass through junctions more quickly, but buses remain trapped in general traffic, the net impact on bus speeds is likely to be negligible.
The only real way to improve bus speeds is to give buses more priority over general traffic. That means building dedicated bus lanes into junctions, rather than relying on marginal tweaks to traffic light timings.
The hidden danger to pedestrians and cyclists
Even more concerning is the potential impact of TfL’s plan on road safety. London’s streets are already dangerous for vulnerable road users, with 130 road deaths recorded in Greater London in 2024. Alarmingly, nearly two-thirds of those fatalities (58%) were pedestrians and cyclists—the highest proportion since records began in 2005.
By increasing traffic flow at junctions, TfL risks making conditions even worse for those walking, cycling, or using wheelchairs. More traffic means more interactions between vehicles and vulnerable road users, particularly at junctions, where a significant proportion of collisions occur.
This move directly contradicts the Mayor’s Vision Zero policy, which aims to eliminate road deaths and serious injuries. Instead of making roads safer, it risks making them even more dangerous.
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A better way forward
While TfL’s traffic light adjustments may be ineffective, there is one measure in its latest plan that could have a meaningful impact: the expansion of lane rental schemes. These schemes, which charge utility companies for roadworks that disrupt bus routes, could help prevent unnecessary delays and improve journey times.
However, far more radical action is needed if TfL is serious about prioritising bus travel. Key steps should include:
- Extending bus lane hours to 24/7 to ensure buses have consistent priority throughout the day.
- Introducing ‘bus gates’—stretches of road where only buses (and sometimes cyclists) are allowed to travel.
- Creating ‘blue paths’, where general traffic is held behind buses rather than overtaking them.
- Removing on-street parking to free up more space for bus lanes.
Time for real leadership
London’s buses are vital to the city’s transport network, carrying millions of passengers every day. But without significant reforms, they will continue to be bogged down in traffic, undermining the Mayor’s wider goals of reducing car dependency and cutting emissions.
The Clean Cities Campaign has already highlighted the slow progress in meeting London’s transport targets. Tweaking traffic lights is merely tinkering at the edges of a much deeper issue. If TfL truly wants to speed up London’s buses, it must take bolder steps—before passengers lose faith in the system altogether.
