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Rumble strips north of the border
The Recumbent Blog got its hands on the installation instructions for continuous milled rumble strips in Alberta, Canada. It’s worth looking at in the context of our discussion of rumble strips to examine what’s good about the approach and what could be improved.
Alberta, Canada's rumble strip installation instructions
In our report on rumble strips, we highlight four common problems with rumble strips that should be addressed in bicycle-tolerable installation: 1. strips that are too wide, 2. grooves that are too deep, 3. strips not placed near the fog line, and 4. strips that are continuous.
Let’s take the width first. Some of the most bicycle-tolerable designs call for 5 inch wide rumble strips, but strips are sometimes 16 or 18 inches wide and even occasionally take up the entire shoulder (see the photo in our previous post). In that context, the one foot wide strip here could be a lot worse.
Second, relatively speaking, 8 mm is a very favorable rumble strip depth for cyclists.
The third issue is placement. Strips should be placed within a foot of the fog line, and the Alberta installation calls for this, which is great. So far the guidance is three for three. The trick with placement is that sometimes implementation doesn’t follow the plan. Sometimes the agency doesn’t even know that the contractors are mis-installing the strips until bicyclists bring it to their attention, so advocates should monitor rumble strip installation to make sure the strips are installed correctly.
In the photo below from the Recumbent Blog, you can see the strip sitting snuggly against the white fog line. The best part of the example below, though, is the six foot remaining ridable shoulder to the right of the strip. Guidance from the US Federal Highway Administration (FHWA) says that strips should not be installed unless there is at least four feet remaining (five if there is a guardrail). Six feet makes this a comfortable ride — and gives drivers plenty of time to correct their trajectory before their fully off the road.
A rumble strip close to the fog line with a six foot shoulder in Alberta, Canada (Photo from The Recumbent Blog)
The fourth potential issue is the only one that I’d suggest they re-visit. These strips are continuous. They do not include any gaps to allow cyclists to cross into the travel lane to avoid debris or rough pavement.
I’d like to thank the Recumbent Blog for bringing up this real life example that gets close to following bicycle-tolerable practices. What we tell state and local advocates is that rumble strips are not going anywhere. FHWA and state DOTs see them as an effective and inexpensive safety tool. The trick for bicycling advocates is to urge agencies not to install rumble strips indiscriminately (i.e. only when conditions call for it and there are sufficient shoulders,) and to follow bicycle-tolerable practices when they do install them.
Darren Flusche
League Policy Director
Flusche joined the League in April 2009 and has a B.A. in history from Syracuse University and a Masters of Public Administration with a concentration in public policy analysis from New York University.
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July 16th, 2010 at 12:50 pm
Nice discussion.
One has to indeed be careful of whom one blames when these are installed wrong. I’ve seen examples of cosmic disconnects between contractors and government, including one case where we had to chew out a contractor for putting up a non-MUTCD sign telling cyclists and motorists to ride side by side in a narrow construction zone lane because the contractor was clueless about the W11-1 / W16-1 sign. Motorists thought we were being willful violators for taking the lane!
One problem, at least where I live, is that the part of the shoulder to the right of the rumble strip is often the filthiest while the fog line or shoulder just to the right of the fog line is cleanest. Whatever advantage one might think one has by riding farther right might be carefully contemplated while one is picking glass out of one’s tires.
But rumble strips are not going away. We have to pick our battles wisely. Perhaps pushing for mandatory recycling and bottle deposit laws are the best we can do in some cases. Back a a misspent youth ago in Suffolk County, NY, such laws were Campagnolo-sent.
July 16th, 2010 at 1:19 pm
Yes, Khal, good point. Shoulder maintenance is one of the less sexy aspects of good rumble strip implementation. It is part of FHWA guidance, but easily ignored by road agencies.
July 16th, 2010 at 4:57 pm
Its easier to target shoulder sweeping in urban or suburban areas where there is less road mile per sweeping vehicle and where one can bring better pressure on local government from local cyclists and advocates. We explicitly put sweeping/maintenance in our county bike plan so we can wave the document at people.
The more serious problems I see are out in the middle of nowhere (and we in New Mexico have lots of “middle of nowhere” to deal with) where sweeping is impractical due to the distances involved and lack of priority. I nearly broke the tandem this year riding over rumble strips on US 84/285 trying to dodge broken glass during the Santa Fe Century. At one point, I noted after an excursion over rumble strips that our front quick release had released.
That’s why a clever way to reduce the tossing of trash onto the shoulders would be good. In Hawaii, the Hawaii Bike League would partner with the Hawaii Sierra Club in an effort to get a mandatory deposit/bottle bill passed.
Another way is to support State Bike Routes. If one can get these designated for higher levels of preventative and corrective shoulder maintenance, its worth the fight.
http://nmshtd.state.nm.us/main.asp?secid=15675
July 18th, 2010 at 9:15 am
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