MoDOT rumble strips--progress and continued discussion

For those of you keeping track, MoBikeFed has been engaged with MoDOT on its rumble strip policy for about 10 years now. Rumble strips are a significant impediment to safe bicycling on MoDOT roads. Because MoDOT's network of roads is so much larger than that of most state DOTs, these include rural roads as well as many of the major urban roads.

MoDOT's old-style rumble strips were wide, deep, and right in the middle of the shoulder. The new style is narrower and under the white "fog line"

Powerful local and national interests are allied in favor of the installation of rumble strips, so the role of MoBikeFed and other bicycle advocacy organizations has been to promote rumble strip designs and standards that minimize the effects of rumble strips on bicyclists and still allow safe bicycling on roads where rumble strips are installed.

The process has been one of discussion, compromise, and continued change and adaptation rather than a complete victory or final solution. MoDOT's current rumble strip design standards are not ideal for bicyclists and the discussion will continue.

Significant problems with current rumble strip design:

• Rumble strips are very deep and harsh, enough so to cause a bicyclist to lose control if the rumble strip is hit. (The argument for deep rumble strips is that less aggressive designs will not be noticed by large vehicles including semis. The deeper, more aggressive rumble strip design allows the strips to be narrower, which is helpful for bicyclists.)
  
• Rumble strips are continuous. If, for instance, a bicyclist is on the shoulder side of the rumble strip and their is debris on the shoulder, it is awkward and dangerous to cross the rumble strip to avoid the debris.
  
• Rumble strips may be placed on shoulders as narrow as 2 feet wide. A two or even three foot shoulder is perfectly usable for bicycling--but not if it has a rumble strip.

Despite the problems noted above, MoDOT's current rumble strip design has a number of features advocated by MoBikeFed and other bicycle advocacy groups that make them friendlier for bicyclists:

• Rumble strips are omitted entirely on roads where the posted speed limit is less than 50 MPH
  
• Rumble strips may be omitted on urban roads
  
• Rumble strips are generally omitted on minor roads--the quiet country roads bicyclists often enjoy
  
• The rumble strips are narrow--about 8 inches wide, compared with the 16-24 inches originally proposed
  
• Rumble strips are partially placed under the "fog line"--the white line at the right of the travel lane. Although this is not a perfect solution, it still allows bicyclists to operate either in the travel lane (in situations where that is the preferred alternative) or in the shoulder (in situations where that is the best alternative). Because the white paint is slippery, operating directly on the white line is usually not a good option for bicyclists, so in a sense about half of the rumble strip is placed in an area that is undesirable for bicycling anyway.
  
• Rumble strips stop several hundred feet before each intersection. This was done specifically to allow bicyclists to move laterally to prepare for a left- or right-hand turn at intersections without being hampered in movement by rumble strips.

MoBikeFed will continue to work on your behalf to create an even better rumble strip standard for Missouri. Short-term goals are to work for periodic gaps in the rumble strip pattern (something like 40 foot rumble strips alternating with 10 foot gaps) and to work for a less deep and aggressive type of rumble strip that will be less dangerous to bicyclists.

If you would like to weigh in with MoDOT on this issue you can use MoDOT's online feedback form.

More info on MoDOT's rumble strip policy is on page 21 of MoDOT's Practical Design Implementation Guide (PDF).