Improving Bicycle Safety in Traffic: Lessons from Michigan
I have long felt that bicycle commuting during the evening rush hour was more stressful and perilous than my morning ride. While motorists tend to be more wary in the morning due to the presence of school children and buses, the evening commute tends to feel a bit like a free-for-all, as if all motorists were trying to qualify for the Indianapolis 500 at the exact same time. Well…now I have definitive data to back my up my intuition. It turns out that 3:00 p.m. to 6:00 p.m IS the most dangerous time period of the day to be a bicyclist out on the roadways.
On April 30, 2012, the Michigan Department of Transportation (MDOT) released a detailed and comprehensive report on roadway safety that was prepared by T.Y. Lin International and Western Michigan University (WMU). Entitled, Sharing the Road: Optimizing Pedestrian and Bicycle Safety and Vehicle Mobility, the report with appendices is several hundred pages long, but contains a wealth of information from the 2005-2010 time period that is useful to bicycling advocates and others. Here are a few juicy tidbits pertaining to bicycling:
- Youth (ages 5-15) involvement in bicycle crashes in Michigan is higher than national statistics: 32.4% compared to 26.8%.That means nearly one-third of all young people in Michigan are involved in a bicycle crash and one-forth of those (25.3%) are fatal/serious.
- In all other age classifications, Michigan’s rate is lower than the national data, except for those 65-74 years old.
- Men are involved in 81% of all fatal bicycle crashes in Michigan.
- Bicycle crash locations are nearly evening spilt between intersections and non-intersections (49% to 51%).
- Despite the perceived safety of a signalized intersection, almost half of all fatal and serious injury bicycle accidents (48.9%) took place at signalized intersections.
- More than half of all fatal/serious injury bicycle accidents took place on two-lane roads (56.6%), followed by five-lane (13.8%); four-lane (12.9%) and three-lane (9.7%).
- Together, 25 and 30 mph streets (neighborhood and downtown streets) accounted for 75.5% of all bicycle crashes, but the majority of fatal bicycle crashes took place on streets/roads with a speed limit of 45 mph or greater even though they comprised only 19% of the crashes.
- Between 3:00 p.m. and 6:00 p.m., 27.2% of fatal and serious bicycle crashes took place, followed by 6:00 p.m. to 9:00 p.m. (21.8%); and 12:00 p.m. to 3:00 p.m. (18.5%).
- The day of the week made almost no difference for fatal and serious injury bicycle crashes in the 2005-2010 time frame, ranging between a low of 151 on Sundays to a high of 220 on Wednesdays. The average is 192 and the weekday average is 205.2.
- More than two-thirds (71.2%) of all fatal and serious injury bicycle accidents took place during daylight hours and 89% where when the pavement was dry.
- Alcohol was not involved for the motorist or bicyclist in 70% of the fatal and serious injury crashes.
Now that the sad and sorrowful crash data have been accumulated, what next? To MDOT’s credit the report also identified and studied many possible solutions at length. Some of the results of this analyses may be a bit disappointing, particularly for road diet advocates like myself. Among the improvements analyzed related to bicyclists at intersections were bulb-outs, roundabouts, bicycle signal detection, bike boxes, two-stage bike left turn, combined bike/turn lane, and bicycle signals. Along corridors, improvements considered included paved shoulders, road diets, raised medians, bike lanes, shared lane markings, buffered bike lanes, colored bike lanes, contra-flow bike panes, left side bike lanes, and cycle tracks.
- Roundabouts showed an overall decrease in all types of crashes by 35%, injury crashes by 76% and fatal crashes by 89%. They also are one of the most expense improvements, costing between $250,000 and $500,000.
- Road diets reduced all crash types anywhere from 14% to 49%.
- Raised medians reduce all crashes by 40%, and by as much as 69% at unsignalized intersections.
- Bike lanes can reduce bicycle crashes by 50% and are most appropriate on streets with average daily traffic volumes exceeding 3,000 and posted speeds between 25 and 35 mph.
- Buffered bike lanes are preferable on roadways with speed limits exceeding 35 mph.
- Shared lane marking (sharrows) were found to increase bicyclist visibility to motorists, reduce the occurrence of wrong-way riding, and riding on sidewalks.
- Green, high-visibility bike lanes will be added to the next version of the Manual of Uniform Traffic Control Devices (MUTCD). Where tested, these have been shown to improve safety through a variety of measurements.
Unfortunately, specific numerical data for some of the options listed above were not provided (perhaps due to a low number of previous studies). Instead summary charts were utilized that rated improvements with terms such as “reduce,” “no difference,” “better,” and “worse.” A separate column rated the estimated cost for each from “low” to “high.” The review also did not appear to judge improvements in combination, but instead each on it’s own merits.
The preparers of the study did make a number of useful recommendations to MDOT and provided a terrific document entitled Best Design Practices for Walking and Bicycling in Michigan. Here is a list of the most bicycling-pertinent recommendations from the report (not as many as I had hoped for):
- It is suggested that this could be the basis for a separate Michigan Design Guide chapter dedicated to accommodating bicycles (instead of under “Miscellaneous Structures”).
- It is recommended that this guidance (shared lane markings) should be incorporated in the Michigan Manual on Uniform Traffic Control Devices (MMUTCD).
- It is recommended that MDOT should permit the establishment of target speeds as a potential solution when conducting speed studies, using the ITE proposed recommended practice Context Sensitive Solutions in Designing Major Urban Thoroughfares for Walkable Communities.
All in all, the report is very comprehensive and does address most, if not all safety issues raised by bicyclists. At the same time, it would have been useful to include data on the effects of combined improvements and consider the mobility challenges that bicyclists and pedestrians face with same degree of importance that is given to motorist mobility. There always seems to be an inherent default towards the motorist, when in fact the term “transportation” is meant to apply all forms, not just cars.
by Rick Brown