First, welcome to the ACA Forums!
You brought up a sore topic for cyclists! Rarely do I appreciate them while on a bike.
I used to work for the Transportation Research Board (TRB) which is part of the National Academy of Sciences (NAS). They are the ones who basically provide Congress and a lot of state governments the recommendations based on their mostly unbiased scientific studies. Believe it or not, they do in-depth studies on hundreds and hundreds of transportation topics. You name most any area of transportation, and it has probably been studied at one time or another. They are the ones who come up with the recommendation for curve radius of am exit lane at X speed, the slope of the road to assist drainage, plane tire specs, train crossing signs placement, the design of all the various bike lanes, ferry loading/off loading design, speed limits for a given road type, etc.
Heck, I once helped plan a 3-day conference on the various types of roundabouts. I thought how the hell can they speed 3 days on roundabouts. In fact they probably need 5 or 6 days and it was very surprisingly a fascinating conference. Now the 3-day conference on concrete (for various road types) was dull but again, they needed more time. And since these are government conferences, they start a 8am and finish around 4:30pm. It is not like a meeting at a resort by any means. They are there to learn.
I know they have done repeated studies on rumble strips. They studied the various designs, effects, etc. Heck, I would not be surprised if they did a 3-day conference on it and I am very serious. TRB tries to factor in all forms of user data when then do a study, i.e. the driver/pilot/etc., the passengers, the community, the users, costs, maintenance, etc. to come up with what is "best". The problem is defining what is "best". If the point of a rumble strip is to prevent vehicular accidents, the non-vehicular factors may not be as an important consideration.
Anyway, once they determine what is "best" for that particular study (each study may have a different focus), other committees (say the Pedestrian and Bicycle Committee or the "Tire Materials" Committee or the Concrete Materials Committee) may decide to review the data and give feedback from their perspective and then the topic may or may not be restudied. I sat in on some of the Ped & Bike committee meetings occasionally to learn about it. The rumble strip topic is usually a multiple session topic at the Annual Meeting. But then there are something like 2,000 sessions or paper presentations for the 5-day Annual Meeting.
The problem is if accident data suggests the road may need rumble strips to reduce vehicular accidents but there is not the money to widen the road to incorporate a shoulder for cyclists. Additionally, even though there are probably national guidelines for what rumble strips to use where and when, if a highway engineer does not do the research to find out about the various studies, the guidelines do no good. "Hey Bubba, let's put a 12" strip right down the ol shoulder. That sound good to you?" TRB and the NAS do not have enforcement or legal authority, again, they just make recommendations.
So say you have a state that has a highway with somewhat high traffic counts. Say the road is a tad narrower than what is preferred and has little to no shoulder. If the strip is put it inside the outside white line, then cars don't have as much room to maneuver and then may run over it much more frequently. This may indeed cause accidents as the driver overreacts. If the put it on the outside of the white line, then cyclists may very well have an accident. If on top of the line (actually the line is on top of the strip), then the line painter has to be very careful when painting as as not to move off the strip. Remember, a line is typically painted several times over the years before a road is repaved.
Then you factor in the rumble strip design and pavement material. They both can definitely effect the level of noise the rumble strip makes. This goes back to the design and its intended purpose. Is it to give a definite notice before they go off the road entirely or more of a warning before they fade off onto the full-width shoulder? Is the rumble strip deep or shallow? Are the groves 1" across (front to back) or 2". If the engineer who came up with the highway paving specs didn't do their research, a poorly designed rumble strip may have been given in the specs to the road contractor. Part of it also may be the rumble strip installer. They, the road contractor, or the government entity may not care as much or be as particular.
But overall, my guess is that usually a poorly designed strip is primarily due to lack of design research then lack of funding (in case a shoulder needs to be added).
For instance, I hate it when they have a 3' wide shoulder and then put a 12" wide and somewhat deep rumble strip in the middle of the shoulder. Trikes are totally screwed but even 2-wheeled bikes don't have much room to maneuver. Granted, I have been on several wide, shallow rumble strips that were more of an annoyance than a pain but those are far between. Or why can't they put a 4" wide strip directly on the painted line and let us have that 12" of shoulder (usually because the usable road is not wide enough)?
My solution? I would love to get the engineers to actually ride a bike on the road with the proposed style of rumble strip design to show them what that specific rumble strip design and placement entails for that highway.
How do we change this lack of decent design? Honestly, I do not know other than possibly getting active with your local and state transportation department. The various studies ARE out there to the various transportation professionals if they bother to do the research AND try to think that cyclists may use the road.
I know this may not answer your question but I hope it gave you a little background.
Tailwinds, John
