National Academies Press: OpenBook

A Guide for Reducing Collisions Involving Bicycles (2008)

Chapter: Section I - Summary

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Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
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Page 1
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Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
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Page 2
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Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
×
Page 3
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Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
×
Page 4
Page 5
Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
×
Page 5
Page 6
Suggested Citation:"Section I - Summary." National Academies of Sciences, Engineering, and Medicine. 2008. A Guide for Reducing Collisions Involving Bicycles. Washington, DC: The National Academies Press. doi: 10.17226/13897.
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SECTION I Summary Introduction Bicycling has been a form of human transportation for hundreds of years and remains a healthy and enjoyable alternative to today’s primarily automobile-centric transportation patterns. Before the invention of the automobile, the League of American Wheelmen led efforts to develop and improve America’s roadways, leading to our modern system of roads and highways. Bicycle safety problems have a long history in the United Stated, dating back to 1896 when a motor vehicle collided with a bicycle on a New York City Street—the first recorded automobile crash. More than a century later, safety continues to be a primary concern for modern bicyclists, with the challenges of traffic congestion, increasing distances between destinations, larger vehicles, and higher speeds. Bicyclists are recognized as legitimate roadway users. The Federal Highway Administration (FHWA) bicycle program provides guidance on numerous issues which include examples of statutory language emphasizing that bicyclists are part of the transportation system and concludes that bicyclists “should be included as a matter of routine” in the planning, design, and operation of transportation facilities (FHWA, 1999). The American Association of State Highway and Transportation Officials (AASHTO) notes that bicycle use is recognized as “a viable transportation mode,” and that “All highways, except those where cyclists are legally prohibited, should be designed and constructed under the assumption that they will be used by cyclists” (AASHTO, 1999). With any roadway facility a potential bicycle facility, it is important to understand and accommodate bicyclists. The safety interests of bicyclists are sometimes in conflict with the interests of motorists. This conflict arises primarily from the substantially different characteristics of the two modes of transportation. Although bicycles can be ridden on most types of roads, the design interests of accommodating higher motor vehicle traffic volumes and speeds during peak hour congestion may create conditions that are less safe for bicyclists. This guide includes road treatments, countermeasures, and other options that support a balanced transportation system. Safety concerns can significantly influence a person’s decision to bicycle for transportation or recreation. Bicyclists inherently understand that they are vulnerable road users. However, understanding bicyclist safety issues has proven difficult for engineers, planners, and facility designers. Traditionally, safety problems have been identified by analyzing police crash reports, and improvements have been made only after crashes have occurred. Such methods are not sufficient to fully understand and effectively address bicyclist safety concerns; waiting for crashes before responding with countermeasures carries a high price because many bicycle crashes tend to be severe. Bicycling has received increased attention in recent years as a mode of transportation that should be encouraged for a variety of reasons. In 1994, the U.S. Department of Transpor- tation presented the National Bicycling and Walking Study (NBWS) to the U.S. Congress, I-1

which, in addition to documenting the state of bicycling and walking in the United States, contained two overall goals (USDOT, 1994b): • Double the number of total trips made by bicycling and walking in the United States from 7.9 percent to 15.8 percent of all travel trips. • Simultaneously reduce by 10 percent the number of bicyclists and pedestrians killed or injured in traffic crashes. Congress adopted the Study’s goals, effectively creating a directive to Federal transportation agencies to implement the Study’s Nine-Point Federal Action Plan with 60 specific action items for the Office of the Secretary, Federal Highway Administration (FHWA), National Highway Traffic Safety Administration (NHTSA), and Federal Transit Administration (FTA); and a Five-Point State and Local Action Plan with a range of suggested activities for state and local agencies. In addition, Congress has vastly increased Federal funds available for bicycle-related projects with the adoption of ISTEA in 1991, TEA-21 in 1998, and SAFETEA-LU in 2005. Federal transportation spending on bicycling and walking increased from $6 million in 1990 to more than $422 million in 2003 (Raborn, 2004). Progress has been made on the two NBWS goals. The goal of reducing injuries and fatalities by 10 percent has been surpassed. The number of bicyclist and pedestrian fatalities decreased by 18 percent from 1993 to 2003; bicyclist fatalities dropped by 23.3 percent. The number of bicyclists injured in collisions with motor vehicles decreased by 35.3 percent over the same time period (Raborn, 2004), but these decreases may reflect a downward trend in overall bicycling as much as they indicate safety improvements. Since 2003, however, these trends have reversed: as of 2005, the decrease in bicyclist fatalities from 1993 had decreased to less than 4 percent. So, progress has been made on reducing bicyclist injuries and fatalities, but that progress appears now to be eroding. The NBWS goal of doubling the percentage of walking and bicycling trips has not been accomplished, although the number of trips increased and perhaps doubled. In 1990, there were an estimated 1.7 billion bicycling trips; in 2001, that number had almost doubled to 3.3 billion. Combined walking and bicycling trip numbers increased from 19.7 billion to 38.6 billion. The percentage of bicycle trips, however, increased a mere one-tenth of a percent (from 0.7 percent to 0.8 percent), while combined trips increased from 7.9 percent to 9.5 percent. The disparity between the large increase in trip numbers and the small increase in trip percentages can be explained by the explosive growth in total reported trips of all modes; from 249 billion in 1990 to 407 billion in 2001 (Raborn, 2004). With current Federal policies and guidance and the resources now available to improve conditions for bicycling, any agency charged with construction, operation, and maintenance of transportation infrastructure must devote attention to accommodating safe bicycling activity. The trends show that progress is indeed being made to meet the national walking and bicycling goals, but opportunities remain to improve facilities and programs for bicyclists. General Description of the Problem Since the nationwide peak of 1,003 bicyclist fatalities reported in 1975 in the Fatality Analysis Reporting System (FARS), traffic-related bicyclist fatalities and injuries have trended downward. Over the past 10 years, the number of fatalities has generally trended downward, SECTION I—SUMMARY I-2

SECTION I—SUMMARY although the most recent 2 years have shown a clear increase (see Exhibit I-1). The NHTSA National Center for Statistics and Analysis (NCSA) reports that fatalities have been from 2 to 25 percent below the number killed in 1995 (830 bicyclists) for 8 of the 10 years, even while all motor vehicle crash fatalities have shown increases since 1995. In 2005, 784 bicyclists (5.5 per- cent below the 1995 level) were killed in collisions with motor vehicles, an increase of 8 percent from 2004 and nearly 27 percent from the 10-year low of 622 bicyclist fatalities recorded in 2003. The 2005 number represented about 2 percent of those killed in all motor vehicle crashes for the year, a proportion that has remained relatively constant in recent years. A total of 45,000 bicyclists were estimated injured nationwide in crashes with motor vehicles in 2005, which represents an increase in both the number of bicyclists injured and the proportion of all traffic injuries (2 percent) from 2004 (NHTSA, NCSA, from General Estimates System [GES], Exhibit I-2). Reported injuries do not include crashes not reported to the police, even if the bicyclist may have been injured, but this figure likely captures most serious roadway crashes involving motor vehicles. While the number of bicyclist injuries and fatalities fluctuates from year to year, potentially reflecting economic conditions, variations in weather, riding exposure and other trends, as well as chance variation, the general downward trends have been good news. The recent increases in fatalities over the past 2 years, however, dramatically reinforce the need for adoption of strategies to reduce collisions involving bicyclists. I-3 EXHIBIT I-1 Bicyclist fatalities from 1995–2005 (NHTSA, NCSA, Traffic Safety Facts 2004 Data: Pedalcyclists, from FARS data) 0 100 200 300 400 500 600 700 800 900 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 EXHIBIT I-2 Bicyclist injuries from 1995 to 2005 (NHTSA, NCSA, 1995–2004; data from GES estimates)

Crashes involving bicycles and motor vehicles are complex phenomena, and classifying the different events into mutually exclusive categories is a formidable task. Cross and Fisher (1977) were the first researchers to develop and apply crash ‘typology’ for bicycle crashes as part of a NHTSA response to the 1,003 bicyclist fatalities in 1975. NHTSA also developed a coder’s handbook for typing bicyclist crashes to address this issue (NHTSA, n.d.). Similar typology was used in the FHWA study by Hunter et al. (1996). In a six-state study of 3,000 bicycle crashes taken from hard copy police reports, the most frequent bicycle/motor vehicle crash types were as follows: Crossing Path Crashes % of All Crashes • Motorist failed to yield to bicyclist (includes drive out/through 21.7 at intersections and at Midblock/driveway locations) • Bicyclist failed to yield to motorist at an intersection 16.8 • Bicyclist failed to yield to motorist, midblock 11.8 • Other crossing path crashes 7.2 57.5 Parallel Path Crashes • Motorist turned or merged into bicyclist’s path 12.2 • Motorist overtaking bicyclist 8.6 • Bicyclist turned or merged into motorist’s path 7.3 • Other parallel path crashes 7.4 35.5 Specific Circumstances Crashes (such as off-roadway, backing vehicle, intentional, and other unusual 7.0 crash types). Crash type proportions varied by state, however, likely reflecting differences in urbanization and other characteristics. The types of crashes that were most severe were parallel path, rather than crossing path, crashes. Crossing path crashes occur at junctions (intersections or driveways) and more often in urbanized areas where speeds are often slower. Crash type severity was measured by the percentage of bicyclists involved in each type of crash that were seriously injured or killed, as shown below: Crossing paths • bicyclist turning error (23.8 percent) • bicyclist failed to yield, midblock (22.1 percent) • bicyclist failed to yield, intersection (20.1 percent) Parallel paths • operator loss of control (34.6 percent) • wrong-way operator (most often the bicyclist) (32.1 percent) • motorist overtaking (29.4 percent) • bicyclist turn/merge into the path of a motorist (25.2 percent) Children tend to be over-represented more often in crossing path crashes including ride outs at non-intersection locations (such as driveways) and at intersections and are more likely to fail to clear an intersection or make a turning error. In parallel path crashes, children are more likely to make turn/merge maneuvers in front of motorists; however, adults tend to SECTION I—SUMMARY I-4

SECTION I—SUMMARY be over-represented in other parallel path crashes (which tend to be more severe) including motorist over-taking crashes, motorist turn/merge in front of bicyclist on a parallel path, as well as in bicyclist overtaking motorist crashes. Although declining in recent years, the fatality and injury rates among child riders, in particular the 10 to 15 year age group, remain the highest per capita among any age group. About one-fifth of bicyclist traffic fatalities were between the ages of 5 and 15 in 2004. The share of fatalities accounted for by those under age 16 has been declining in recent years, from 37 percent in 1994 to 21 percent in 2004 (NHTSA, 2004). Both the number and the proportion of fatalities among adults ages 35 and up has been increasing, from 36 percent of all bicyclist fatalities in 1994 to 59 percent in 2004. Crashes involving adult bicyclists ages 25 and up tend to be more serious, resulting in fatal and disabling injuries a higher percentage of the time. These trends may be due in part to where adults ride, the types of crashes adults tend to be involved in, and changes in the bicycle riding population. Objectives of the Emphasis Area Reducing the number and severity of collisions involving bicyclists requires strategies that are targeted towards addressing the main factors that lead to collisions. Based on what is known about bicycle-related crashes, the following objectives—targeted both toward locations where crashes occur as well as toward the causal factors of crashes—are most likely to reduce the number and/or severity of crashes: • Reduce bicycle crashes at intersections • Reduce bicycle crashes along roadways • Reduce motor vehicle speeds • Reduce bicycle crashes at midblock crossings • Improve safety awareness and behavior • Increase use of bicycle safety equipment • Reduce influence of hazards Each of these strategies can be accomplished through a variety of the 23 individual strategies (i.e., treatments) presented in Exhibit I-3. Most strategies will work best when used at multiple locations, so that they become standard and expected by roadway users, and in combination with other treatments, so that multiple causal factors are addressed. In addition, many of the strategies may help accomplish more than one single objective. It is important for transportation professionals and others charged with improving conditions for bicyclists to choose the right combination of treatments to accomplish the maximum desired effect with the available resources. Finally, those involved in transportation engineering, planning, design, education, and safety should be aware of Safe Routes to School (SRTS) programs as a potential comprehensive technique for improving the transportation safety for children traveling to and from school. SRTS programs are comprehensive programs that involve making safety-related changes to I-5

the built environment, implementing extensive child bicyclist (and pedestrian) safety education, and increasing traffic law enforcement around schools. SRTS programs are also intended to increase the number of children walking or bicycling to school, so programs usually include encouragement components as well. More about SRTS, including the full range of comprehensive activities and projects, information about selecting appropriate activities, and evaluation strategies can be learned from the National SRTS Clearinghouse (established by the U.S. Department of Transportation) at: http://www.saferoutesinfo.org. SECTION I—SUMMARY I-6 EXHIBIT I-3 Emphasis Area Objectives and Strategies Objectives Strategies A. Reduce bicycle crashes at intersections A1. Improve visibility at intersections (T) A2. Improve signal timing and detection (T) A3. Improve signing (T) A4. Improve pavement markings at intersections (T) A5. Improve intersection geometry (T) A6. Restrict right turn on red (RTOR) movements (E) A7. Accommodate bicyclists through roundabouts (T) A8. Provide an overpass or underpass (T) B. Reduce bicycle crashes along roadways B1. Provide safe roadway facilities for parallel travel (T) B2. Provide contraflow bicycle lanes (T) B3. Improve bicyclists’ visibility (T) B4. Improve roadway signage (T) B5. Provide bicycle-tolerable shoulder rumble strips (T) C. Reduce motor vehicle speeds C1. Implement traffic calming techniques (P) C2. Implement speed enforcement (T) D. Reduce bicycle crashes at midblock crossings D1. Improve driveway intersections (T) D2. Implement access management (T) E. Improve safety awareness and behavior E1. Provide bicyclist skill education (T) E2. Improve enforcement of bicycle-related laws (T) F. Increase use of bicycle safety equipment F1. Increase use of bicycle helmets (P) F2. Increase rider and bicycle conspicuity (T) G. Reduce effects of hazards G1. Fix or remove surface irregularities (T) G2. Provide routine maintenance of bicycle facilities (T) P = proven; T = tried; and E = experimental

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A Guide for Reducing Collisions Involving Bicycles Get This Book
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TRB's National Cooperative Highway Research Program (NCHRP) Report 500, Vol. 18, Guidance for Implementation of the AASHTO Strategic Highway Safety Plan: A Guide for Reducing Collisions Involving Bicycles provides strategies that can be employed to reduce collisions involving bicycles.

In 1998, the American Association of State Highway and Transportation Officials (AASHTO) approved its Strategic Highway Safety Plan, which was developed by the AASHTO Standing Committee for Highway Traffic Safety with the assistance of the Federal Highway Administration, the National Highway Traffic Safety Administration, and the Transportation Research Board Committee on Transportation Safety Management. The plan includes strategies in 22 key emphasis areas that affect highway safety. The plan's goal is to reduce the annual number of highway deaths by 5,000 to 7,000. Each of the 22 emphasis areas includes strategies and an outline of what is needed to implement each strategy.

Over the next few years the National Cooperative Highway Research Program (NCHRP) will be developing a series of guides, several of which are already available, to assist state and local agencies in reducing injuries and fatalities in targeted areas. The guides correspond to the emphasis areas outlined in the AASHTO Strategic Highway Safety Plan. Each guide includes a brief introduction, a general description of the problem, the strategies/countermeasures to address the problem, and a model implementation process.

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