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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

This report is an archived publication and may contain dated technical, contact, and link information
Publication Number:  FHWA-HRT-12-053    Date:  November 2012
Publication Number: FHWA-HRT-12-053
Date: November 2012


Casual Carpooling Scan Report


Despite the long history of dynamic ridesharing (sometimes called slugging or casual carpooling) in several U.S. cities, little research has been undertaken to understand its challenges and opportunities. The Federal Highway Administration’s (FHWA’s) Exploratory Advanced Research (EAR) Program has been exploring how slugging works, taking a two-part approach (scanning and focus groups) to studying the mechanics, logistics, and success of the practice. 

Many academics and entrepreneurs have been looking at ways to facilitate dynamic ridesharing through technological means. These efforts are most often justified as feasible by pointing to the success of the dynamic ridesharing systems that exist in the three cities evaluated. These three systems have no formal leadership or management; rather, they have evolved at the grassroots level to fulfill a need for carpools created by the presence of high-occupancy vehicle (HOV) lanes. These naturally occurring dynamic ridesharing systems operate by having drivers and riders meet at central, easily accessible locations, such as park-and-ride lots, where they create instantaneous carpools based on desired destinations. The robust commuting system is highly successful and long-lasting (30+ years in the case of Washington, DC) and serves thousands of people each weekday.

This scan trip evaluation brought a select group of academics and transportation professionals (see table 1) to the slug/casual carpool lines in each of the three cities to observe the dynamic ridesharing phenomenon, to meet with State and regional transportation officials, and to talk to dynamic ridesharing participants. The overall goal of studying these ridesharing systems is to evaluate whether to fund research on the potential for and value of expansion or replication. This report was produced by the scan team participants, who outlined what they learned at the dynamic ridesharing sites and identified what gaps exist in the data and research. The report suggests where funds and efforts could be targeted for expanding or replicating the dynamic ridesharing systems. The foundational knowledge gained on this scan will serve as a jumping-off point for future projects, collaborations, and system expansion.

The EAR Program is supporting qualitative research by assembling focus group participants from those who slug or casual carpool to work in three cities—Washington, DC; Houston, TX; and San Francisco, CA—to gain first-hand knowledge from both the drivers and riders. The first set of focus groups was held on May 22 and 23, 2012, in Washington, DC; the second set was held on July 11 and 12, 2012, in Houston, TX; and the final set of focus groups took place on August 21 and 22, 2012, in San Francisco, CA. For the focus groups, an independent firm contracted by FHWA asked participants about their experiences, practices, satisfaction, suggestions, and decisions related to slugging. The research firm will develop a report that summarizes the results of each of the focus groups as well as overall lessons learned.

Table 1. Scan team participants.
Dr. Mark Burris Texas A&M University
Ed Christopher FHWA, Resource Center
Patrick DeCorla-Souza FHWA, Office of Innovative Program Delivery
Allen Greenberg FHWA, Office of Operations
Susan Heinrich San Francisco Bay Area Metropolitan Transportation Commission, 511 Traveler Information Program
Dr. Jim Morris Carnegie Mellon University
Marc Oliphant Department of the Navy
Eric Schreffler ESTC Consulting
Peter Valk Transportation Management Services (TMS) Consulting
Phil Winters University of South Florida, Center for Urban Transportation (CUTR)


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