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Public Roads - September/October 2013

September/October 2013
Issue No:
Vol. 77 No. 2
Publication Number:
Table of Contents

Guest Editorial

Driving Away Congestion Through Exploratory Research


Almost everyone agrees that congestion is detrimental to the Nation’s well-being. Congestion contributes to air pollution, inefficient energy usage, and ineffective movement of people, goods, and services. Even as early as 1920, Public Roads was reporting that the transportation community had realized the need for research about the movement and operation of vehicles on roadways to enable engineers to build better roads and traffic controls.

Nearly a century later, the transportation system faces different operational challenges. The Federal Highway Administration’s Exploratory Advanced Research (EAR) Program, a bridge between basic and applied research, aims to address those challenges. The program conducts high-risk, high-yield research to help identify promising long-term opportunities to improve the transportation system.

In many urban areas, the system capacity has maxed out operationally, and “rush hour” has become “rush hours.” Yet carpooling has dropped from 20 percent modal share in 1980 to 11 percent in 2008--despite longer commutes and increased traffic. Researchers with the EAR Program are examining the causes for the decline and how the Nation might be able to tap into the empty seats in private vehicles to help move more people in fewer cars using the existing road system.

In this issue of Public Roads, an article titled “Fill Those Empty Seats!” explores how dynamic ridesharing might be one solution. More flexible than traditional carpooling, dynamic ridesharing increases the number of riders per vehicle. The concept is ripe for technology applications, which could enable users to access social networks to find rideshare opportunities, rate the experience, and reimburse drivers for expenses.

In addition, the article discusses a form of ad hoc ridesharing known as slugging, or casual carpooling, in which potential carpoolers meet at a specific place and rides are not prearranged. Driven by the incentive of access to the high-occupancy vehicle (HOV) lanes, casual carpooling, like other forms of ad hoc ridesharing, saves time and money for drivers and riders. Legend has it that casual carpooling started when drivers wanting to use the HOV lanes began stopping at bus stops to offer rides to waiting passengers. Riders received free nonstop travel, and the drivers were able to use the highly coveted, faster HOV lanes--a win-win situation. In three major cities--Houston, TX; San Francisco, CA; and Washington, DC--the phenomenon organically grew into workable commuting systems, without any government or for-profit involvement.

An upcoming issue of Public Roads will feature an article that discusses several recently completed projects under the EAR Program. The focus is on improving mobility and increasing safety. The article will include information about how the transportation community is exploring cooperative vehicle-highway automation systems, freeway merge assistance, development and evaluation of selected mobility applications, and advanced traffic signal control algorithms.

In addition to addressing mobility challenges, the EAR Program encompasses improvements in planning, building, renewing, and operating safe, congestion-free, and environmentally sound transportation facilities. The program also seeks to leverage advances in science and engineering that could lead to breakthroughs for critical current and emerging transportation issues.

To secure broad scientific participation and extensive coverage of advanced ideas and new technologies, FHWA engages stakeholders throughout the EAR Program’s processes. Not only do stakeholders participate in identifying and scoping topics, but also expert panels and peer reviews help ensure the technical quality of sponsored research. Communicating research results through these networks, as well as through published research reports, helps ensure that the transportation community can benefit from the findings.

To become involved in the program, go to



Debra S. Elston
Director, Office of Corporate Research, Technology,
and Innovation Management Federal Highway Administration