A new government report on air quality includes a recommendation to remove speed humps.  This prompted an ‘alarmed’ joint response from Living Streets, Cycling UK and the Campaign for Better Transport, pointing out that lives could be put at risk by speeding drivers, and not do much to help air quality anyway. (They were also unimpressed that the government is giving such low priority to charging drivers in clean air zones.)

In Enfield Independent this week, one letter writer got excited about the prospect of removing speed humps, calling it a “breath of fresh air”.  The following are some thoughts on the issue from a Better Streets member…

The vast majority of city streets come with speed limits of 20 or 30mph. Just as clear is the knowledge that a significant minority – and in some cases, a majority – of drivers do not respect this legal requirement. This is despite the Highway Code highlighting that the speed limit is the absolute maximum. The same code goes on to add that within this absolute limit there are times when even slower speeds are entirely appropriate (“It is often not appropriate or safe to drive at the maximum speed limit”), like urban areas where there is a risk of pedestrians, especially children, stepping unexpectedly into the road; when sharing the road with pedestrians and cyclists; on streets where there are likely to be pedestrians, cyclists and parked cars; and when passing parked vehicles. That seems to cover most streets in Enfield.

Most readers will surely agree that such fine intent is essentially ignored. With most cars perfectly capable of exceeding 100mph and many capable of more than 150mph, there is no internal restraint on a wayward driver to follow the rules. And far too many don’t.

Speed humps are not the issue: driving too fast for the road conditions and the law is the issue.

As a result, traffic engineers have installed external features to slow down drivers, the most common of which are speed humps. Those speed bumps are in place is because drivers go too fast – illegally. Take away the speed, and the speed humps could also be taken away. In other words, let’s focus on the actual problem. Speed humps are not the issue: driving too fast for the road conditions and the law is the issue. But when it comes to car-centric anger, the issue of speed humps is often rolled out: the causes of back pain, broken cars and pollution. And pollution is currently a hot topic. Let’s ignore the fact that a sizeable proportion of air pollution – the particulates we breathe – come about by the very process of driving: tyre and brake wear. Take away the car and replace it with feet or pedals, and a large slice of that issue simply disappears.

The other main component of polluted, human-health damaging air is NO2; a direct result of fossil fuel burning, especially diesel. The government has been over a legal barrel for a number of years by spectacularly failing to meet legal requirements to bring such pollutants within acceptable bounds. Losing in UK courts, they were eventually instructed by the Supreme Court to sort it out. Failing in that, the Supreme Court told them to sort it out. So they planned this time to get local authorities to sort it out … some distant way down the line.

The focus on car-borne air pollution and the government’s lamentable record of failure on air quality has suddenly shifted to those hated speed bumps

Enter Michael Gove. In what a cynic may consider a masterful piece of PR, the focus on car-borne air pollution and the government’s lamentable record of failure on air quality has suddenly shifted to those hated speed bumps. The argument is that the humps produce a bit extra braking / acceleration, and hence emissions, versus steady driving in conditions without humps. Now a sensible driver may well conclude that if you drive at a constant speed of, say, 18mph on a road with speed humps, you won’t need to  slow down or speed up.  They’d be right. But that wouldn’t make such a good story, distracting the media from the government’s ongoing lamentable failure to act effectively (and legally).

So we now see ministers’ latest national air quality strategy which suggests “improving road layouts and junctions to optimise traffic flow, for example by considering removal of road humps”, as an alternative to charging Clean Air Zones (CAZs). And not surprisingly we can read press letters all about those hated speed humps and their effects on back-pain, car damage and air pollution.

But campaigners then asked Michael Gove “to provide any evidence held by your Department that the removal of speed humps would improve air quality, and that this outweighs any possible public health disbenefits due to increased road injuries and fatalities”.

No answer.

DEFRA (the Department for the Environment and Rural Affairs) were also challenged to state what its evidence was. No evidence was cited.

TRL (the since privatised Transport Research Laboratory) inputted that research has shown that traffic calming measures can cause an increase in harmful tail pipe emissions and CO2, with speed humps tending to have the largest increases. But it went on to say that at the same time it’s important to remember that speed humps do not significantly contribute to the total amount of harmful vehicle pollutants that are created. TRL didn’t add that by removing illegal and inappropriate speed, or switching journeys to active means, speed humps could be dispensed with entirely.

Other commentators have made the case that even if speed bumps did increase air pollution, the effect would be nowhere near the safety impact they bring in slowing down vehicles,

Doubtless the story will continue. After bad backs, car damage and air pollution will likely come a different scourge of the times highlighting just why those awful speed bumps need to be ripped out. My money is on speed bumps having some negative effect on self-driving cars: the polarity of batteries, their connections, control interfaces or … .. well I’m sure we’ll hear when the time of the self-driving and electric car comes, and another argument is required.

Want to get rid of speed bumps? Then slow down – or better still, walk, cycle or take the bus.