Note: this is an old post- originally drafted nearly a year ago, but recently I’ve been reminded of it by the surprising results of a poll, showing that 80% of people want a default 20 mph limit, and the also interesting observation here.
On to my old post:
I was all ready to go into a full, frothing-at-the mouth rant about something that seems to be gaining ground: Twenty’s Plenty, a campaign for the default speed limit to be 20mph, not 30.
Instead, I’ll try to give a reasoned argument. I’ll set my stall out here: I’m a driver, I speed at times. I’m also a cyclist and pedestrian, like I’d imagine a lot of people are.
I think many speed limits are too low. Some are too high- tiny residential estate roads with a 30 limit, for example, but many main roads are crippled with a low limit: many urban roads around towns were built with a 40 limit, which has been lowered.
I also think that 20 limits have a lot of merit, but feel strongly that that is far too low for a default. 20 limits are fine in areas where no sane individual would be doing much more anyway: housing estates, shopping areas, near schools, for example, but the 30 mph limit is entirely appropriate for a great many roads. I’m sitting writing this looking out at a road that has a 30mph limit that is generally exceeded a little- a residential road that happens to be a B road, and carry a reasonable amount of traffic- and the only thing that seems dangerous is the occasional nutter at 60+.
My big concern is that if 20 is the new 30, we’ll see it on almost everything. I’m also concerned about some of the things presented on their website.
What’s wrong with 30 mph?
Well the 30 mph limit was actually brought in as the national speed limit for built-up areas in 1934. Prior to that the 1903 Motor Car Act designated a specific category for the Motor Car. It also raised the speed limit to 20 mph. The Road Traffic Act of 1930 abolished the 20 mph limit for cars of less than 7 people. This led to such an increase in road deaths that just 4 years later the 1934 Road Traffic Act introduced the 30 mph speed limit in built-up areas. Whilst in 1934 this may have been an acceptable limit, the huge increase in the number of motor vehicles on the roads has created a huge imbalance in vulnerability between pedestrians or cyclists and motor car users.
This is happily forgetting that while, yes we have much, much greater traffic density, at the time of the 30mph limit being increased, a typical car was the Austin 7, a car with cable brakes, initially only operating on the rear wheels. If you drive even a 1960s or 1970s car today, you’ll find the handling, grip levels, and stopping distances are vastly inferior to today, as is the pedestriam safety should you hit someone.
As to vulnerability of pedestrians and cyclists, they’re always much more vulnerable- and vehicle drivers will always need to remember this: the aim should be not to do that at all, I would suggest.
What are the benefits of 20 mph?
Whilst the safety benefits may justify 20’s Plenty on their own, there are additional real benefits for lower speeds. Traffic noise drops considerably, as does pollution. Your street becomes a far more pleasant place to be and this encourages people to walk or cycle instead of using the car.
Pedestrians, as a rule, will (or should) be on a footpath, except in a pedestrianised area, which should, of course, be devoid of vehicles, and personally, when I cycle, I find that cars at 20mph (in a traffic-calmed street, for example) are very awkward: their speed is far to close to mine, so far too much time is spent closer to a moving car than I’d like- in a 30 limit they’ll be past and gone. As to the noise and pollution, I’d like to see some hard facts there: 20mph may necessitate use of a lower gear, *increasing* noise and emissions- most medern cars will just pull 30 mph in 4th gear, but 20 will definitely need 3rd.
I’d also suggest that those people that are going to walk or cycle will already do so: people that want to drive will continue to do so.
It’s a complex, difficult situation.
I’d personally have more support for 20mph as a limit if it’s applied sensibly, and limits are reviewed wholesale, and meaningful data is recorded and acted upon, not just an unconsidered reaction.
I’m also of the opinion that many people would like a 20 limit in their own roads, but not anywhere else, and I think this observation is quite revealing:
This is anecdotal evidence that most drivers want to travel above the 30mph limit, and definitely above 20, which again, is somewhat at odds with the survey’s results.
I’m really thinking here that we’re seeing a “it’s OK for me to drive at above 20/30, but anyone else doing it is a dangerous lunatic” and “it’s Ok to drive above 20/30, except in my road, where it’s dangerous”. I’ve also noted that more than one prominent supporter of 20mph limits seem to be non-drivers (and indeed, non cyclists), which I’d say probably makes it hard to make an objective judgement about what constitutes the best balance of speed, emissions, and safety, though given the alarming lack of awareness of the laws of physics governing a ton and a half of car, it’s clear that there’s plenty of drivers that can’t, too.
Looking at figures, oddly, there’s a suggestion that there’s been an increase in casualties in 20mph limits, and slight reductions elswhere, but the problem here is that we don’t know if this is simply because there’s more 20 mph roads to get injured in. There’s a fairly clear indication that there’s less severity of injury, as you’d expect. It’s my opinion (but this is only opinion) that traffic-calmed areas or very low speeds cause pedestriams to take more risk, but that the lower traffic speeds mean that the chance of an collision resulting is much lower, and that if it does, then injuries will be less severe.
The second link above draws the distinction between 20mph limits and 20mph zones: Zones have traffic calming such as humps, chicanes, and road markings as both physical and psychological devices, limits alone don’t have these- it’s clear the zones are much more effective, and these are usually in narrow, dense streets where it’s quite clear that 30mph would be unacceptably risky.
The problem here is that the data isn’t clear and uniform, there’s conficting and incomplete data, which seems to be no way to make a decision. The debate rages on…