NICE released a d(r)aft consultation on combating traffic related air pollution. It was widely misreported across the media.
One of the more lurid headlines came from the Telegraph, a bastion of anti-science.
The NICE report is very weak on this. Indeed, they felt compelled to put out this statement:
The committee looking at the matter found only weak evidence from 2 Dutch studies, so the recommendation is only desirable.
There still is a problem with the recommendation.
Speed bumps force motorists to slow down. What they don’t do is force motorists to speed up. They are not meant to.
Motorists speed up after a speed bump because the road in between is designed to driven down at 30mph or more.
Typically, speed bumps appear for 2 reasons: firstly, to cut drivers’ speed near a school or in a residential neighbourhood; secondly, to make a street less attractive to ratrunning.
The road where the speed bumps were installed was most likely a 30mph road beforehand. It probably features corners with wide radii, all optimised to move cars quickly.
The junction above has speed bumps on each of its three arms. But drivers quickly speed up in between, because it has corners you’ll more likely find at Brand’s Hatch. It is the road design that induces fast driving.
Putting in speed bumps is pointless if the road in between does not induce slower speeds. If that junction had tight corners, then drivers would drive more slowly. With chicanes, alternative road surfaces a slower speed is induced.
And all things considered cars going at 20mph or less in residential areas is much better for everyone concerned.
The report makes another recommendation regarding where cycle routes should be sited:
1.5.1 Avoid siting cycle routes on highly polluted roads. Ideally use off-road routes or quiet streets.
1.5.2 Where busy roads are used consider:
- Providing as much space as possible between the cyclist and motorised vehicles.
- Using dense foliage to screen cyclists from motor vehicles, without
- reducing street ventilation so that air pollution can disperse.
- Reducing the time cyclists spend at busy sites, including some junctions, where this can be done without increasing the time that other groups spend exposed to poor air quality.
I’m all for quiet routes if only they went somewhere and afforded the cyclist a safe environment to cycle in. At present UK quietways are generally a normal street with some modal filtering at best, often merely a recommended route with no dedicated cycle infrastructure. And they tend to give up when traffic is busier. Hackney in London is a prime example.
The motivation for this recommendation is weak:
The committee was aware from members’ own experience that air pollution concerns were among the factors putting some people off cycling.
The Sustrans Cycle to Work Survey said:
Even if all 281 respondents who said “Other” meant concern about air pollution that still pales into nothing compared to the 3723 who said “Distance” or “Safety”.
To be fair, had air pollution been an option some would have picked it.
Elephant in the Room
The main problem with the report is its addressing symptoms, not the root cause. The root cause is the number of polluting vehicles on our roads. The measures in the report amount to mitigating the effects of polluting traffic.
NICE fail to adequately address that our cities are designed for moving people by cars, where commuting by another means is not or very poorly planned for. Belfast is such a city.
This week, Belfast has once again found itself at the top of an unwelcome table:
(Illustrated with a picture of York Street.)
The answer lies not in using screening foliage, though it would be nice way to stop motorists encroaching on cycleways. It lies in getting people out of cars, by improving access for public transport, for walking and cycling.
It is better for us (improved health), for our city (liveability), our region (economically) and our world (climate change).
There is no alternative; Chris Hazzard, NI Minister for Infrastructure says:
“Moving people in and out of Belfast city is good for business; moving cars is not.
What are we to do after York Street? Are we to bulldoze half of Great Victoria Street because we need two extra lanes in Great Victoria Street? Are we to demolish Belfast City Hall because we need a bigger roundabout at Belfast City Hall?
We need to talk about moving people, not cars, in and out of Belfast.”