Evaluation of Shared Lane Markings
PDF files can be viewed with the Acrobat® Reader®
Foreword
The Federal Highway Administration's (FHWA) Pedestrian and Bicycle Safety Research Program's overall goal is to increase pedestrian and bicycle safety and mobility. From safer crosswalks, sidewalks, and pedestrian technologies to growing educational and safety programs, the program strives to make it safer and easier for pedestrians, bicyclists, and drivers to share roadways in the future.
This study was part of a larger FHWA research study to quantify the effectiveness of engineering countermeasures in improving safety and operations for pedestrians and bicyclists. This particular project focused on applications of shared lane markings, particularly the sharrow design, for bicycles and motor vehicles that have not yet been comprehensively evaluated in terms of effectiveness. The effort involved data collection and analysis to determine whether the sharrows resulted in changes in positioning of bicycles and motor vehicles on roadways, as well an examination of their interactions.
This report is of interest to engineers, planners, and other practitioners who are concerned about implementing pedestrian and bicycle treatments as well as city, State, and local authorities who have a shared responsibility for public safety.
Monique R. Evans
Director, Office of Safety
Research and Development
Notice
This document is disseminated under the sponsorship of the
U.S. Department of Transportation in the interest of information exchange. The
U.S. Government assumes no liability for the use of the information contained in this document.
The
U.S. Government does not endorse products or manufacturers. Trademarks or manufacturers' names appear in this report only because they are considered essential to the objective of the document.
Quality Assurance Statement
The Federal Highway Administration (FHWA) provides high-quality information to serve Government, industry, and the public in a manner that promotes public understanding. Standards and policies are used to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
Technical Report Documentation Page
| 1. Report No.
FHWA-HRT-10-041 |
2. Government Accession No. |
3 Recipient's Catalog No. |
| 4. Title and Subtitle
Evaluation of Shared Lane Markings |
5. Report Date
December 2010
|
|
6. Performing Organization Code
|
| 7. Author(s)
William W. Hunter, Libby Thomas, Raghavan Srinivasan, and Carol A. Martell |
8. Performing Organization Report No.
|
|
9. Performing Organization Name and Address
Highway Safety Research Center
University of North Carolina
CB #3430, 730 Martin Luther King Boulevard
Chapel Hill, NC 27599-3430
|
10. Work Unit No. (TRAIS)
|
11. Contract or Grant No.
DTH61-01-C-00049
Task Order #25
|
| 12. Sponsoring Agency Name and Address
Office of Safety Research and Development
Federal Highway Administration
6300 Georgetown Pike
McLean, VA 22101-2296 |
13. Type of Report and Period Covered
Technical Report:
October 2006–March 2010 |
|
14. Sponsoring Agency Code
|
15. Supplementary Notes
The Contracting Officer's Technical Representative (COTR) was Ann Do, HRDS-30.
|
| 16. Abstract
Shared lane markings help convey to motorists and bicyclists that they must share the travel way on which they are operating. The purpose of the markings is to create improved conditions for bicycling by clarifying where bicyclists are expected to ride and to remind motorists to expect bicyclists on the road. The purpose of this study was to evaluate the impact of several uses of shared lane pavement markings, specifically the sharrow design, on operational and safety measures for bicyclists and motorists. Experiments were conducted in three cities. In Cambridge, MA, there was interest in experimenting with the placement of sharrows at a 10-ft spacing from the curb to prevent dooring from parked vehicles. In Chapel Hill, NC, sharrows were placed on a busy five-lane corridor with wide outside lanes and no parking. In Seattle, WA, sharrows were placed in the center of the lane on a downhill portion of a busy bicycle commuting street. Prior to the sharrows, a 5-ft bicycle lane was added to the uphill portion of the street in conjunction with shifting the center line. A variety of hypotheses were examined, and results were generally positive. Sharrows can be used in a variety of situations, and increased use should serve to raise motorist awareness of bicyclists or the possibility of bicyclists in the traffic stream. It is recommended that trials similar to those performed in this study be continued in other locations and traffic settings to improve guidance for users.
|
| 17. Key Words
Shared lane markings, Sharrows, Bicycles |
18. Distribution Statement
No restrictions. This document is available to the public through NTIS:
National Technical Information Service
5301 Shawnee Road
Alexandria, VA 22312
http://www.ntis.gov |
|
19. Security Classification
(of this report)
Unclassified
|
20. Security Classification
(of this page)
Unclassified
|
21. No. of Pages
87
|
22. Price
N/A
|
| Form DOT F 1700.7 |
Reproduction of completed page authorized |
SI* (Modern Metric) Conversion Factors
TABLE OF CONTENTS
CHAPTER 1. INTRODUCTION
CHAPTER 2. LITERATURE REVIEW
CHAPTER 3. METHODS
CHAPTER 4. CAMBRIDGE, MA, EXPERIMENT
CHAPTER 5. CHAPEL HILL, NC, EXPERIMENT
CHAPTER 6. SEATTLE, WA, EXPERIMENT
CHAPTER 7. CONCLUSIONS AND DISCUSSION
ACKNOWLEDGMENTS
REFERENCES
LIST OF FIGURES
LIST OF TABLES
- Table 1. Motor vehicle proximity to bicycles, Cambridge, MA
- Table 2. Motor vehicle lane changes, Cambridge, MA
- Table 3. Parked motor vehicle events, Cambridge, MA
- Table 4. Avoidance maneuvers and conflicts, Cambridge, MA
- Table 5. Bicyclist and motorist yielding behavior, Cambridge, MA
- Table 6. Bicyclist responses during interactions with motor vehicles, Cambridge, MA
- Table 7. Motorist responses during interactions with bicyclists, Cambridge, MA
- Table 8. Bicycle to parked motor vehicle, Cambridge, MA
- Table 9. Bicycle to passing motor vehicle, Cambridge, MA
- Table 10. Motor vehicles in travel lane to parked motor vehicles, Cambridge, MA
- Table 11. Distance between tire and curb, Cambridge, MA
- Table 12. Average speeds before and after sharrows, Cambridge, MA
- Table 13. Analysis of speed data, Cambridge, MA
- Table 14. Direction of travel, Chapel Hill, NC
- Table 15. Gender of bicyclists, Chapel Hill, NC
- Table 16. Motor vehicle proximity to bicycles, Chapel Hill, NC
- Table 17. Motor vehicles that changed lanes, Chapel Hill, NC
- Table 18. Safety of the overtaking motor vehicle, Chapel Hill, NC
- Table 19. Avoidance maneuvers, Chapel Hill, NC
- Table 20. Bicyclist and motorist yielding behavior, Chapel Hill, NC
- Table 21. Motorist responses during interactions with bicyclists, Chapel Hill, NC
- Table 22. Distance between bicycle and curb (motor vehicle not present), Chapel Hill, NC
- Table 23. Distance between bicycle and passing motor vehicle, Chapel Hill, NC
- Table 24. Distance between motor vehicles in the travel lane and the curb, Chapel Hill, NC
- Table 25. Bicyclist position and direction observations for entire study period, Chapel Hill, NC
- Table 26. Sidewalk riding before and after sharrow installation (both directions), Chapel Hill, NC
- Table 27. Sidewalk riding before and after sharrow within travel direction, Chapel Hill, NC
- Table 28. Wrong-way riding before and after sharrow installation (both directions), Chapel Hill, NC
- Table 29. Wrong-way riding within travel direction, Chapel Hill, NC
- Table 30. Results of laser speed studies (mi/h) before and after sharrow implementation, Chapel Hill, NC
- Table 31. Comparison of before and after speeds (mi/h) at sharrow and comparison sites, Chapel Hill, NC
- Table 32. Gender of bicyclists, Seattle, WA
- Table 33. Motor vehicle proximity to bicycles, Seattle, WA
- Table 34. Motor vehicle changed lanes, Seattle, WA
- Table 35. Bicycle riding position, Seattle, WA
- Table 36. Bicyclist took lane, Seattle, WA
- Table 37. Parked motor vehicle events, Seattle, WA
- Table 38. Avoidance maneuvers, Seattle, WA
- Table 39. Yielding behavior of bicyclists and motorists, Seattle, WA
- Table 40. Bicyclist responses during interactions with motor vehicles, Seattle, WA
- Table 41. Motorist responses during interactions with bicyclists, Seattle, WA
- Table 42. Analysis of average spacing data, Seattle, WA
- Table 43. Distribution of the percentage of spacing between bicycles and parked vehicles, Seattle, WA
LIST OF ACRONYMS AND ABBREVIATIONS
AADT | Average annual daily traffic |
ACS | Adaptive control system |
ADT | Average daily traffic |
Aimsun | Advanced Interactive Microscopic Simulator for Urban and Non-urban Networks |
ASC MIB | Actuated signal controller management information base |
ATMS | Advanced Traffic Management Systems |
CCD | Central composite design |
CEP | Conflict ending point |
CICAS | Cooperative Intersection Collision Avoidance System |
CMF | Crash modification factor |
CORSIM | Corridor Simulation |
CSP | Conflict starting point |
DCS | Detection Control System |
DeltaS | Maximum speed differential |
DeltaV | Change between conflict velocity |
DR | Deceleration rate |
FHWA | Federal Highway Administration |
FRESIM | Integrated Traffic Simulator |
HUTSIM | Helsinki Urban Traffic Simulation |
ITE | Institute of Technical Engineers |
MaxD | Maximum deceleration rate |
MaxS | Maximum speed of vehicle |
MDSHA | Maryland State Highway Administration |
OPAC | Optimization Policies for Adaptive Control |
PET | Postenchroachment time |
PHF | Peak-hour factor |
PI | Performance Index |
RHODES | Real Time Hierarchical Optimized Distributed Effective System |
SCATS® | Sydney Coordinated Adaptive Traffic System |
SCOOT | Split Cycle Offset Optimization Technique |
SPUI | Single-point urban interchanges |
SSAM | Surrogate Safety Analysis Model |
TEXAS | Traffic Experimental Analytical Simulation |
TOD | Time of day |
TRANSIMS | Transportation Analysis and Simulation System |
TTC | Time to collision |
V/C | Volume to capacity |
Y+AR | Yellow plus all red |
|
