London’s 20 mph Roads Are Safer—So Why Are Motorcycle Deaths the Exception?

Motorcyclists should not pretend otherwise merely because many riders dislike blanket speed restrictions.

Yet buried inside the same research is a finding that deserves far more attention than it has received: motorcycle fatalities did not fall.

That does not disprove the value of 20 mph limits. It does expose an uncomfortable gap in the way motorcycle safety is discussed. When the overall figures improve, policymakers celebrate the success. When riders fail to share fully in that improvement, the explanation is often left unexplored.

The Research Is Stronger—and Older—Than the Latest Headlines Suggest

Transport for London published its long-term study on 21 May 2025. It analysed 157 borough-road 20 mph schemes introduced between 1989 and 2013, comparing police-recorded injury collisions during the three years before and after each scheme.

The researchers also compared those changes with the background trend across all London borough roads during matching periods. That matters because road casualties were already declining for reasons unrelated to any particular speed-limit scheme.

Within the 20 mph areas, people killed or seriously injured fell by 34%, from 395 to 260. Fatalities fell by 40%, from 15 to nine. Total collisions declined by 35% and total casualties by 36%. The corresponding reductions across the control roads were considerably smaller.

These are not projections or opinions. They are the study’s reported results, based on STATS19 collision records. Transport for London’s original research summary explains the method and its limitations.

The study does not show that changing a sign alone produced every improvement. TfL acknowledges that speed limits were not the sole cause, and some areas also received physical traffic calming, junction changes or other safety measures. Nor does research into schemes installed by 2013 automatically prove that every modern 20 mph policy will work equally well on every kind of road.

Nevertheless, the direction of the overall evidence is persuasive: those particular London schemes were associated with fewer and less severe collisions beyond the general reduction occurring elsewhere.

The Motorcycle Result Is Not Simply “No Benefit”

This is where the reporting needs greater care.

The Motorcycle Action Group’s submission to Parliament highlights figures from the TfL analysis showing motorcycle killed-or-seriously-injured casualties falling by 31%, from 78 to 54. The control-road reduction was only 7%.

That suggests riders did receive a substantial benefit in injury severity or frequency. It would be wrong to tell motorcyclists that 20 mph schemes made no difference to them.

However, TfL also states that motorcycle fatalities were the exception to the wider improvement: they did not change.

We do not have enough motorcycle-specific detail in the public summary to explain why. The fatality numbers may be very small, making percentage comparisons unstable. The crashes may involve different mechanisms from those affecting pedestrians, cyclists or car occupants. Reduced impact speed may lessen many injuries without preventing the particular combinations of error and force that prove fatal to an unprotected rider.

Those are possibilities—not findings. Claiming that poor driver observation, road surfaces or junction design caused the unchanged fatality figure would go beyond the published evidence.

The honest conclusion is simpler: a potentially important exception has been identified, but not publicly explained.

Why Isn’t Motorcycle Safety Being Investigated Separately?

Motorcycles do not behave like narrow cars. Riders can filter through stationary traffic, disappear behind windscreen pillars and be destabilised by surfaces that a four-wheeled vehicle barely notices. A collision that damages a car’s bumper can cause life-changing injuries to someone on a motorcycle.

That is why aggregate road-safety figures can conceal as much as they reveal.

If pedestrian deaths fall, cycling injuries fall and car-occupant casualties fall, an overall total may look excellent even when a smaller road-user group experiences a different outcome. Motorcyclists form a minority of traffic, so their results can be statistically overwhelmed by the much larger numbers travelling by car or on foot.

MAG is right to demand that evidence be separated by road-user type. This is not special pleading. It is the minimum information required to understand whether a policy protects everybody in the same way.

A serious response would ask what happened in each fatal motorcycle collision within the study areas. Was another vehicle turning across the rider’s path? Was the crash at a junction or on an open section of road? Was excess speed involved? Did the road layout, visibility, surface or traffic-calming design contribute? Did traffic move onto surrounding routes?

Without that work, “motorcycle fatalities did not change” becomes a footnote rather than a research question.

This Should Not Become Another Culture War

There is a temptation to turn every 20 mph discussion into a referendum on motorists’ freedom. That would waste the most valuable part of this evidence.

Lower speeds reduce stopping distance and impact energy. Riders, like every other road user, benefit when a driver has more time to see them and a collision occurs with less force. The fall in motorcycle KSI casualties is consistent with that basic safety principle.

But a lower limit cannot repair a pothole, remove diesel from a roundabout or make a distracted driver look properly before turning. It cannot substitute for junction design that accounts for motorcycles, meaningful roads policing, rider training or campaigns aimed at observation failure.

The fair Motorbike Mad position is therefore neither “20 mph limits do not work” nor “the overall improvement settles every question”. It is this:

London’s schemes appear to have made roads safer, including reducing serious motorcycle casualties. The unchanged rider-fatality result now deserves the same urgency as the headline success.

What Transport for London Should Publish Next

TfL could improve confidence by releasing a clear motorcycle-only annex showing the absolute fatality, KSI and slight-injury figures; the types and locations of the crashes; which schemes included physical traffic calming; and whether the motorcycle results were statistically significant.

It should also explain whether the fatal collisions shared any preventable features and what changes followed.

That would help authorities outside London. A targeted 20 mph zone around a school, a residential scheme with raised tables and a blanket restriction across a through-route are not interchangeable interventions. Neither are central London streets, Welsh villages and rural English A-roads.

Councils considering new limits need to understand which combinations of speed management, engineering and enforcement produced the benefit—and whether any design features created fresh risks for riders.

Motorcyclists should be willing to accept good evidence even when it challenges instinct. Policymakers must reciprocate by investigating riders as a distinct road-user group rather than assuming that a positive total tells the whole story.

The London study gives strong grounds for believing that 20 mph schemes can save lives. Its motorcycle exception does not overturn that conclusion.

It asks the next question—and riders deserve an answer.