Cover Image

Not for Sale

View/Hide Left Panel
Click for next page ( 100

The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement

Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 99
SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-53 (Continued) Strategy Attributes for Bicycle-tolerable Rumble Strips (T) Attribute Description Appropriate measures used to evaluate the safety effectiveness of the bicycle-tolerable rumble strips include data on bicycle-only crashes or loss-of-control bicycle injuries related to rumble strip encounters. Vibration levels experienced by bicyclists while traversing the rumble strip pattern can be used as a surrogate measure to evaluate the tolerability of rumble strip patterns. Rumble strip patterns that generate lower levels of vibrations for bicyclists are more tolerable for bicyclists. Associated Needs None identified. Organizational and Institutional Attributes Organizational, An agency should have a written rumble strip policy that takes bicyclists into Institutional, and consideration. Policy Issues Issues Affecting Rumble strip programs can be implemented quickly (i.e., within a year of an agency Implementation Time deciding to proceed). They can be implemented as components of both new construction and rehabilitation projects. Costs Involved Costs for installing rumble strips are minimal. An average cost of approximately $0.82 per meter ($0.25 per foot) or $1,640 per kilometer ($2,640 per mile) for the installation of milled-in rumble strips on the shoulders on both sides of two-lane roads has been reported. Incremental costs would be even less for rumble strips being implemented concurrently with reconstruction or resurfacing of a highway. Training and Other None identified. Personnel Needs Legislative Needs None identified. Other Key Attributes None identified. Information on Organizations Currently Implementing this Strategy Appendix 7 illustrates the policy developed by the Pennsylvania Department of Transportation to guide the installation of bicycle-tolerable shoulder rumble strips. The Washington Department of Transportation developed a shoulder rumble strip installation policy that includes required coordination with the WSDOT Bicycle/Pedestrian Advisory Committee. More information is available at: folio/Rumble_Strips.pdf. Objective C--Reduce Motor Vehicle Speeds Strategy C1: Implement Traffic Calming Techniques (P) General Description Traffic calming refers to traffic management techniques and engineering measures intended to enhance the safety of road users and, in many cases, improve the livability of a community. V-73

OCR for page 99
SECTION V--DESCRIPTION OF STRATEGIES The goals of traffic calming are to reduce motor vehicle speeds, traffic volume, or both. Reducing motor vehicle speeds has the potential to reduce both the frequency and severity of bicycle/motor vehicle crashes, and reductions in vehicular volumes ultimately decrease bicycle exposure to motor vehicle traffic. Several of the companion guides provide detailed information on traffic calming techniques intended to reduce motor vehicle speeds. The reader is referred to these guides for more detailed information on implementing traffic calming techniques. In particular, the reader is directed to the following objectives and strategies in the respective guides: NCHRP Report 500, Volume 10: A Guide for Reducing Collisions Involving Pedestrians Objective 9.1 C--Reduce Vehicle Speed Strategy 9.1 C1--Implement road narrowing measures Strategy 9.1 C2--Install traffic calming--road sections Strategy 9.1 C3--Install traffic calming--intersections NCHRP Report 500, Volume 5: A Guide for Addressing Unsignalized Intersection Collisions Objective 17.1 H--Reduce operating speeds on specific intersection approaches Strategy 17.1 H2--Provide traffic calming on intersection approaches through a combination of geometrics and traffic control devices The remainder of this section presents issues specifically related to traffic calming and bicycles. In 1994, FHWA published the National Bicycling and Walking Study, FHWA Case Study No. 19: Traffic Calming, Auto-Restricted Zones and Other Traffic Management Techniques--Their Effects on Bicycling and Pedestrians (USDOT, 1994a). Several of the more relevant findings from this case study are as follows: European experience clearly shows bicycle use often increases after traffic calming projects are completed. This could, in part, be explained by the fact that traffic calming projects are often designed to prioritize bicycle transportation. One European study reported a doubling of bicycle use and an increase in bicycle crashes after the completion of a traffic calming project. Although the frequency of bicycle crashes had risen, the crashes were primarily non-injury crashes. The city of Palo Alto (California) has installed traffic calming measures and created a priority street for bicycles (i.e., a bicycle boulevard). The purpose of a bicycle boulevard is to provide (a) a throughway where bicyclists have priority over vehicular traffic, (b) a direct route that reduces travel time for bicyclists, (c) a route that reduces conflicts between bicyclists and motor vehicles, and (d) a facility that promotes and facilitates the use of bicycles as an alternative mode for all purposes of travel. Traffic calming engineering measures intended to reduce vehicle speeds can be divided into three categories: vertical, horizontal, and narrowing. Exhibit V-54 shows an example of incorporating a bicycle lane within the roadway cross section, resulting in narrower lane widths. Drivers see only the travel lanes as available road space, so the roadway appears narrower than it is (Oregon DOT, 1998). Bicyclists may experience problems in traffic calmed streets where they have to use the same space as motor vehicles, in particular with humps and other vertical measures (Van Schagen, 2003). In these situations, bicyclists' comfort and safety can be improved by V-74

OCR for page 99
SECTION V--DESCRIPTION OF STRATEGIES EXHIBIT V-54 Trees and Colored Bike Lanes Make a Roadway Appear Narrow (Oregon DOT, 1998) concentrating the vertical elements in the center of the street, leaving space at both sides, so bicyclists can avoid the traffic calming device, or by designing the traffic calming measures with the bicyclists in mind (e.g., designing speed humps that are more tolerable for bicyclists). Vertical measures in streets that are built on a slope should be avoided at all times. Horizontal measures such as road narrowing can also leave separate space for bicyclists so they can pass through in a straight line. For more information on traffic calming as it relates to bicycles, Lesson 11 of the FHWA Course on Bicycle and Pedestrian Transportation pertains to traffic calming (see http://www. Strategy C2: Implement Speed Enforcement (T) General Description The intent of this strategy is to reduce motor vehicle speeds through speed enforcement programs. Reducing motor vehicle speeds through speed enforcement has the potential to reduce the frequency and severity of bicycle/motor vehicle crashes. Most highway agencies implement some form of speed enforcement programs in cooperation with local law enforcement agencies. The keys to a successful speed enforcement program are selecting targeted locations and public awareness. A review of recent speed studies and crash data will aid in selecting specific locations for enforcement activities. Input from officers who regularly patrol the streets will be useful in selecting target locations, and input from the general public, including bicycle clubs or local bicyclists, can also be sought. Media attention is also critical in raising public awareness of the program and need for the program. Finally, enforcement activities should be conducted during hours of the day when speeding is most prevalent at the targeted locations. V-75