Bicycling on interstate freeway shoulders--is it safe? Answers from research

For bicyclists planning a trip--cross-country, cross-state, or local--bicycling on the shoulder of an interstate freeway, expressway, or other high-speed road with restricted access and wide shoulders, is often an appealing alternative.

Bicycling the wide shoulder of an interstate freeway or other high-speed, multi-lane road with wide shoulders is often the only available through route for cyclists. Research indicates that 'there is not a large-scale safety problem associated with the use of these highways by bicyclists'

In many cases--especially in Missouri, where bicycleable route alternatives are not plentiful--bicycling a section of an interstate freeway or similar expressway may be the only possible or reasonable way to reach a destination by bicycle.

We don't often recommend bicycling on such roads, especially when alternative routes are available.  But we know that some bicyclists will choose to travel there--and some will have little choice but to travel there. 

This raises the question: Is bicycling on the shoulder of an interstate freeway or similar expressway safe?

Richard Moeur, and traffic engineer from Arizona, crunched the data for over a decades' worth of data on bicycle injuries on Arizona's extensive interstate freeway system, where bicycling is fairly common.

Moeur's conclusion:  This is a relatively reasonable and safe place for experienced adults to bicycle.  Based on this research, the Arizona DOT adopted standards allowing bicycle use of interstate freeway shoulders and making safety recommendations to improve the safety of cyclists who ride there.

Because this is a question that often arises in Missouri, we are making Moeur's full report available here (PDF file--click to download) and quoting his entire conclusion and recommendation below.

Conclusions

The rate of bicycle-motor vehicle crashes on controlled access highways is less than one per year across the entire state of Arizona for over a decade, clearly implying that there is not a large-scale safety problem associated with the use of these highways by bicyclists.

Further changes on the use of controlled access highways by bicyclists must be evaluated in light of the very small percentage of motor vehicle-bicycle crashes occurring on these roadways.

Recommendations

When requested, adjustments should be made to bicycle access on controlled access highways in accordance with PGP 1030 based on sound engineering judgment that recognizes bicyclists as legitimate users of our roadway system.

When such changes are planned, an objective safety evaluation should be made not only of the controlled access route, but of alternate routes as well, focusing on the crash risk to the bicyclist from all sources. Such case-by-case evaluations should take into account the following items on both the controlled access and alternate routes:

• Existing conditions
• Crash history of both routes
• Location and accessibility of destinations
• Cross traffic at intersections and driveways
• Lane and shoulder widths
• Traffic volumes and speeds
• Special hazards such as unretrofitted drain grates, rough pavement, railroad tracks, and rumble strips
• Other specific concerns

Attention to these important issues should result in improved travel for bicyclists, motorists, and other roadway users.

Considerations for Missouri cyclists:

• No bicycling in interstate travel lanes: Travel lanes of interstate freeways in Missouri have a minimum speed of 40 MPH.  Thus, bicycling in the lanes of interstate freeways is prohibited.  However, minimum speed limits to not apply to shoulder areas, and by Missouri law bicyclists (but not motorists) are allowed to travel in the shoulder area of any roadway, unless specifically prohibited. Consider bicycling on such roads only if a wide, continuous shoulder is available.
   
• Experienced cyclists only: Traveling on such roads is generally for experienced, adult bicyclists who are familiar with bicycling in such situations.
   
• Visibility & daylight: Two-thirds of motorist-bicyclist crashes in this study happened at dusk or at night--a disproportionately high amount. Consider carefully before bicycling in such a situation in darkness or when visibility is poor.  Your lighting and visibility that is adequate on local roads with slower speed limits may be inadequate in this situation at dawn, dusk, or after dark.
   
• Off/On-ramps: A common suggestion is to consider exiting at each offramp and re-entering on the onramp; this avoids crossing very wide off-ramp lanes that are used by very high-speed motorized traffic.

Creating a world-class bicycle and pedestrian transportation system in Missouri is one of the primary goals of MoBikeFed's Vision for Bicycling and Walking in Missouri. Defending the right of Missourians to travel unimpeded under their own, human power is an important part of that goal. Researching and publicizing best practices and best available research is an important part of our work to improve the state's nonmotorized transportation system and improve safety for all road users.

Your ongoing membership and generous financial support helps turn our Vision into reality!

File: 

richard-moeur-interstate-freeway-bicycle-safety-study-2002.pdf

arizona-interstate-freeway-bicycle-policy.pdf