AASHTO STANDING COMMITTEE ON RESEARCH
AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS
NCHRP Problem Statement
I.	PROBLEM NUMBER

II.	PROBLEM TITLE
Edge Lane Roads: Operations and Safety in Rural and Urban Areas
III.	RESEARCH PROBLEM STATEMENT
More than 2 million paved road-miles in the US are classified as local and collector roads. The work to add sidewalks and/or bicycle facilities to these roads would cost many billions of dollars and require decades. Many of these roads, especially in rural areas, would require expensive widening for improvements. Because of their lower speeds and volumes, these roads can be good candidates for on-street bicycle and pedestrian facilities.
A new road configuration known as an Edge Lane Road (ELR), which encompasses “Advisory Bike Lanes” and “Advisory Shoulders”, addresses these cost, timeframe and width issues. ELRs provide an on-street space preferentially reserved for bicyclists, pedestrians, and other vulnerable road users within the confines of a standard 2-lane road.
An ELR is a road configuration which provides for two-way motor vehicle (MV) and vulnerable road user (VRU) traffic using a center travel lane and edge lanes on either side. The center lane is dedicated to, and shared by, MVs traveling in both directions. VRUs have the right of way in the edge lanes but MVs can encroach into the edge lanes in order to pass approaching MVs after yielding to VRUs. 

Figure 2 When two MVs meet, they can use the edge lanes to pass.

Figure 1 MVs travel in the center lane. When passing VRUs, no lane change is needed.

A 2013 survey of 21 developed countries showed over half used ELRs. The Netherlands has used this format for more than 50 years and has installed over 1,000 road-kilometers. The U.S. has over 30 installations as of July, 2019. They are safe and effective.
In addition to providing VRU facilities, ELRs may also improve motorist safety on rural low-volume, high-speed roads. Over half of all crashes on these roads are single-vehicle, roadway-departure crashes. The rate of this crash type drops significantly when wider shoulders are provided. By placing motorists in the middle of a road, ELRs create wide shoulders without expensive widening. Preliminary research shows that head-on crash rate can be unaffected or may even go down with ELRs. See https://www.advisorybikelanes.com/rural-abl-project.html for more information.
IV.	LITERATURE SEARCH SUMMARY
The existing domestic research consists of evaluation reports of North American facilities and papers found at https://www.advisorybikelanes.com/more-info.html. 
Other domestic literature includes:
•	FHWA Small Town and Rural Multimodal Networks Guide,
•	Lessons Learned: Advisory Bicycle Lanes in North America, 
•	ABL Design Guide at https://www.advisorybikelanes.com/design-guidance.html,
•	AASHTO Guidelines for Geometric Design of Very Low-volume Local Roads.
Numerous international sources exist but are too numerous to list or summarize here.
V.	RESEARCH OBJECTIVE
Research will consist of the following tasks:
Task 1: Review of current guidance, practice and concerns - A review of international and domestic literature focusing on ELRs, one-way roads supporting two-way traffic, and roads lacking centerlines will be conducted. In addition, outreach to agency representatives will occur to assess existing installations, their characteristics, and lessons learned. This information will be used to summarize current research, summarize current design practices, and discuss the relationship of this information to the North American context.
Task 2: Identify and prioritize critical issues for ELRs - Based on the results of the literature review and synthesis of practice, the research will identify and prioritize the most critical design and operational issues. 
Task 3: Evaluate possibility of retrospective and/or prospective studies – Data on existing installations will be evaluated to assess the value of including it. A protocol would be created for prospective studies. This protocol could be shared through the FHWA Request-To-Experiment process and used for future North American installations.
Task 4: Design a simulator-based experiment – Simulators provide well-controlled conditions and the opportunity to interview drivers about their experience. This perspective will be important to assess the impact of center lane width on choices around speed and passing maneuvers. Simulators can be used to test inaccessible or non-existent features such as channelizing islands, intersection treatments, or colored edge lanes.
Task 5: Design a field-based data collection experiment - Working from the list of prioritized issues, a field-based observational experiment will be conducted. The experiment design will address as many critical issues as feasible. In addition, methods to capture a range of conditions (e.g., center lane width, heavy vehicle %, posted speed limit, etc.) will be explored and data collection locations proposed. 
Task 6: Collect and analyze data - Implement the data collection program and analyze the results to draw lessons on suitable design guidance and street characteristics for ELRs.
Task 7: Develop and publish ELR guidelines - The final product will be a user-friendly set of guidelines for ELR implementation. The guidelines will be research-based, practical, and applicable to practitioners operating in a wide range of contexts. Issues to be addressed in these guidelines would include:
●	ELR safety performance including horizontal separation, traffic calming effects, driver positioning, etc.
●	Design considerations including lane widths, sight distance, road surface treatments, etc.
●	Siting factors including speeds, volumes, heavy vehicle percentage and other characteristics
●	How ELRs compare to other facilities suitable for low-volume, low-speed streets
●	Appropriate ADA guidance for the use of edge lane roads as pedestrian facilities
●	Islands, used internationally to persuade drivers to return to the center lane and calm traffic
●	Walking on ELRs – facing traffic or with traffic?
●	Intersection treatments for ELRs
●	Use of ELRs on rural low-volume, high-speed roads
●	Impact of color in the edge lanes of ELRs
●	Need for public education and measures to aid driver understanding.
VI.	ESTIMATE OF PROBLEM FUNDING AND RESEARCH PERIOD
Recommended Funding: $450,000
Research Period: 24 months
VII.	URGENCY, PAYOFF POTENTIAL, AND IMPLEMENTATION
ELRs can provide facilities for vulnerable road users on hundreds of thousands of miles of paved roads in the United States. They may also reduce the rate of single-vehicle, roadway departure crashes on millions of miles of low-volume, high-speed rural roads by creating wide shoulders.
This research is high priority given ELR’s ability to inexpensively provide facilities for vulnerable road users, its potential to save lives on rural roads, and the likelihood of widespread, rapid adoption.
VIII.	PERSON(S) DEVELOPING THE PROBLEM
Michael Williams, Krista Nordback, Tom Bertulis
IX.	PROBLEM MONITOR
Michael Williams
Email: bikepedx@gmail.com
Phone: 530-859-3468
X.	DATE AND SUBMITTED BY
August 15, 2019