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Report
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Publication Number: FHWA-HRT-10-041
Date: December 2010

Evaluation of Shared Lane Markings

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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

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

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United States Department of Transportation - Federal Highway Administration