KLK566: Improving Passing Lane Safety and Efficiency: Full Description
ITD Research Project 222; Task Order Number UI-13-03
Principal Investigators:
- Ahmed Abdel-Rahim
- ITD Project Manager
- Brent Jennings
FHWA Project Adviser:
- Lance Johnson
Research Problem Statement:
Passing lanes, in two-lane two-way rural highways, provide motorists with the opportunity to pass slow moving vehicles improving the level of service of the operations in these highways. Such passing maneuvers, however, can lead to hazardous situations for the passing vehicle as well as for the opposing traffic. Several head-on fatal and severe injury crashes occur in passing lanes in Idaho either at merge points (where passing maneuvers have continued too far) or just downstream of passing lanes where demand to pass is high. Field observations have shown that some vehicles, including large trucks and recreational vehicles, tend to increase speeds once in the passing lanes. This leads motorists to pass at excessive speeds that may carry into the merge area increasing the risk of a fatal or a severe injury crash. Passing lane safety and efficiency can be significantly improved if the lead vehicles with varying speeds were encouraged to be courteous and maintain a relatively slower speed allowing more vehicles to pass without excessive speeds or reckless weaving maneuvers. This project examines the effectiveness of two low-cost measures that have the potential of influencing the behavior of drivers while on the passing lanes. The two alternatives are: 1) improved signage upstream from and at the passing lanes and 2) alternative striping and lane marking.
Project Objectives:
- Examine the effectiveness of improved signage on the safety and efficiency of the passing lane operations, 2) examine the effectiveness of alternative striping and pavement marking on reducing the speed at the passing lane locations, and 3) document the characteristics of passing lane crashes in Idaho’s two-lane rural state highways. .
Project Tasks
Document the characteristics of passing lanes crashes in Idaho using 2007-2011 Idaho’s crash data.
Review and document improved passing lane signage, pavement marking, and striping alternatives.
Meet with the project’s TOC to identify the passing lane site to be used in this study and the low cost alternatives to be tested as part of this project.
Develop an implementation plan for the improved signage, pavement marking, and striping alternative identified in task 4. This plan will be developed with the project manager and ITD staff.
Collect the before data at the test site. The data collected will include vehicle speeds and headways at different locations along the passing lane area.
Collect the after data at the test site. This task will be conducted after ITD staff implement the improved signage, pavement marking, and striping alternative identified in task 4 at the passing lane test site.
Analyze the before and after data to determine the effectiveness of the improved signage, pavement marking, and striping alternative implemented din the study.
Project final report
Project Communication Schedule:
Monthly project progress report (ITD 771).
Quarterly project meeting with the project's technical oversight committee.
Needs and Requirements:
This research project aligns with Idaho’s Strategic Highway Safety Plan and supports the top performance measure of eliminating fatalities and serious injuries on two-lane rural roadways in Idaho through the implementation of improved signage, pavement marking, and striping alternatives.
Required Outputs:
Project final report (Task 8 in the project's task list)
Implementation:
The low-cost alternatives tested as part of this project provides a test bed that will allow for implementation of improved signage, pavement marking, and striping alternatives throughout the state of Idaho.
Expected Outcomes/Savings to ITD:
Benefits to ITD and to the public from this project include:- low-cost alternatives that have the potential of improving the safety and efficiency of the traffic operations on passing lanes in Idaho’s two-lane rural highways
- reduced head-on collision on passing lanes, and
- increase public awareness of safe and efficient passing maneuvers through the project’s outreach activities.
This research project aligns with Idaho’s Strategic Highway Safety Plan and supports the top performance measure of eliminating fatalities and serious injuries.