Yesterday, I shared a campaign going on in England to lower the speed limits on residential streets to 20 MPH. BikePortland also picked up the story and shared this striking image on stopping distances of a car in ideal conditions if a child suddenly jumped out in the street.
Going up to just 25 MPH increases the stopping distance by 40 feet compared to 20 MPH while the 35 MPH common on neighborhood arterial roads is over 140 feet longer and due to reaction time does not even begin braking until after the stopping point of 20 MPH is reached. At 35, you would have already run over the child before braking begins.
BikePortland points out that the World Health Organization has gone so far as to endorse the lowering of speed to 20 for just these reasons.
Running over someone or getting out of your neighborhood 10 seconds slower? Decent humanity would call for the latter but our current road engineering favors risking the former for expediance.
on Sep 1st, 2010 at 12:57 pm
Bit of a stretch. Most roads with speed limits of 35 around here need to be driven for a long time – would you be content with spending an extra half hour every day to make people slightly safer when they disobey right-of-way control devices? I wouldn’t; but maybe I’m a bad guy.
I’m right there with you about urban streets – but most of our city is not urban; requires long drives; and should not be treated the same as England. Change the development patterns to be more like Hyde Park and I’ll reconsider.
on Sep 1st, 2010 at 2:08 pm
To be clear (I missed earlier thread); West Lynn is not a 35 road. Enfield is (or should be); Lamar is; W 6th is (maybe shouldn’t be). I don’t want to cut car speed limit on Lamar to 20 (although there were those in OWANA who actually said that with a straight face) – we’d be killing the city to save it.
on Sep 1st, 2010 at 2:47 pm
M1EK,
I’m not suggesting major arterial like Lamar be 20 MPH. There are neighborhood arterials like Emerald Forest in my neighborhood or Barton Hills Drive that could use at least a lowering to 25 with some traffic calming. These are residential roads that have been designated as primary roads through the neighborhoods. Traffic calming would add little extra time getting in and out of the neighborhood to people who live there while discouraging the cut through traffic (which 9 times out of 10 are the ones drag racing through the neighborhood to avoid the real transportation corridor roads.)
on Sep 1st, 2010 at 5:34 pm
Signs and enforcement aren’t going to be very effective. It’s too easy to get a driver’s license and there are many people who are going to drive the way they want regardless. The sheer volume of traffic precludes full time enforcement except in targeted zones.
Physical calming is infrastructure with costs (both installation and maintenance). I’m also skeptical about some methods, as I see cars take certain types of bumps at speed.
I support the concept. I just don’t have any creative ideas to make it work.
On a side note, I already drive 20 mph in my neighborhood. Just a habit I picked up long ago. Drives people crazy when they follow me — the same people that completely ignore the posted 25 limit anyway.
on Sep 1st, 2010 at 5:40 pm
RT @austinon2wheels: Update on Is 20 plenty? Stopping distances http://bit.ly/cSj6ii
on Sep 1st, 2010 at 8:18 pm
I like the idea of a 20mph speed limit on residential roads. I think the key is to involve the lobbyists that work for the manufacturers of dash-board-mounted radar detectors.
If the speed limit were that low, and also strictly enforced, the police would be able (and probably thrilled about being able) to write lots of tickets for cyclists. Then, we could start buying handle bar mounted radar detectors. Hey, you know, we could even bring back CB radios! This time mounted in water bottle cages for bikes!
Can’t you just picture it along Shoal Creek?
“Big Elliot, ya gottcha a bear there on White Horse.”
“That’s a big 10-4, good buddy. I’ll catch ya on the flip side.”
And then we can make a movie like ‘Smoky and the Bandit’ except with a guy who transports stolen Hammer Gels across town in his BOB trailer and then flips off a cop and gets away on carbon time trial bike.
My deepest apologies to all of you who were taking this discussion seriously. I’ll try to behave.
on Sep 1st, 2010 at 10:34 pm
RT @austinon2wheels: Update on Is 20 plenty? Stopping distances http://bit.ly/cSj6ii
on Sep 7th, 2010 at 8:26 am
“neighborhood arterials”
Gritting teeth. There’s no such thing; there’s major and minor, period. This kind of redefinition is what got us the Shoal Creek debacle.
Arterials exist to move people through an area and to other areas – not just out of a neighborhood to other areas. Even minor arterials are supposed to be arteries.
You might be thinking of circulators – where through traffic is STILL supposed to be a priority, but not as high speed as arterials; but IIRC Emerald Forest is a minor arterial anyways.
on Sep 7th, 2010 at 12:54 pm
OK, well several of the streets in and out of my neighborhood are being treated like arterials by people outside of the neighborhood looking to cut around the true arterials. These are the folks that routinely drive 10-15 MPH over the posted 25 MPH speed limit and are only temporarily slowed when we complain enough to get a week or 2 of speed enforcement from APD. Unfortunately, attempts to get physical traffic calming from the City of Austin a few years ago were stymied by NIMBY minded neighbors who didn’t want to take an extra 10-20 seconds to get out of our neighborhood to make the streets safer for kids walking to school, joggers, cyclists, etc.
on Sep 8th, 2010 at 11:18 am
Everybody’s traffic calming is somebody else’s nuisance. And everybody exaggerates how fast cars really go – especially when they’re walking or biking – I remember when I worked on the OWANA neighborhood plan, people insisted that cars regularly went 60+ up Blanco and Baylor. Yes, really.