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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

Washington, DC, November 17–19, 2010

The scan members arrived in Washington, DC, on the evening of Wednesday, November 17, 2010, and stayed in Woodbridge, VA, about 48 km (30 mi) south of the city. At 6 a.m. the following morning, the group visited the Horner Road Park-and-Ride lot to interact with and observe the “slugs” (casual carpoolers) who gather there in the hopes of obtaining a ride to Washington, DC, or the surrounding metropolitan area (see figures 1 and 2). The scan members spent approximately 1.5 hours observing and photographing the slug lines, as well as conversing with those waiting to make ride matches.

Early morning photo of a street corner. A Park-and-Ride lot surrounded by trees can be seen in the background; the sun is rising behind the trees. On the left of the photo about 10 people are lining up near a stop sign on the sidewalk. A blue sedan is approaching the line of people to the right of the curb with its headlights on.

Figure 1. Slugs queuing to the left and vehicles approaching the line from the right at Horner Road Park-and-Ride lot.

There are three individual slug lines located at the Horner Road lot, which serve the destination areas of the Pentagon, L’Enfant/Navy Yard, and 18th Street, NW; occasionally there are other destinations, and drivers will sometimes use signs to announce their destination to riders, as shown in figure 3. Scan group members visited each individual line during the course of the morning. At 6:30 a.m., the L’Enfant/Navy Yard line had 45 people queuing to become passengers, whereas the Pentagon line had 6 vehicles waiting for passengers. This difference could lead to several conclusions. Parking may be more readily available at the Pentagon, and thus more commuters might be willing to drive. It could also mean that the busy time for the Pentagon line is earlier than 6:30 a.m. One man waiting in the slug line noted that parking for him (in the Crystal City area of Arlington, VA) can cost $18 per day, which is a strong incentive not to drive. Others pointed out that the slugging volume tends to be lighter on Mondays and Fridays because many Federal workers work 9-hour days and take every other Monday or Friday off.

Two cars are lined up to pick up passengers at a Park-and-Ride lot. The car in front is red and a man is getting in to the passenger side. A woman is walking toward the second car in line, which is black. A parking lot surrounded by autumn trees can be seen in the background.

Figure 2. A slug enters a vehicle at Horner Road Park-and-Ride lot in Prince William County, VA.

The scan group members joined the slug line (i.e., passenger-waiting queue) for the 18th Street corridor with instructions to catch rides individually and then rendezvous at a coffee shop on 14th Street in Washington, DC. The entire group made it to the coffee shop safely (and separately) by slugging. At the coffee shop, the group members convened to debrief one another on their individual slugging experiences. Eric Schreffler of the scan group drove alone in the group’s rental van to 14th Street because there were no slugs to pick up by the time he departed from the Horner Road Park-and-Ride lot. It took Schreffler 1.5 hours to drive to the 14th Street coffee shop by using the general purpose lanes, whereas it took less than 30 minutes for each of the team members who slugged.

A daytime photo of the driver’s side of a gray four-door car. The sun is shining into the car. The car is parked in an almost empty parking lot. In the background past the parking lot is a white building and bare trees. The driver of the car is holding a sign out of his or her window (the writing is too small to see in the photo).

Figure 3. A driver holds up a sign indicating his or her destination.

At 9 a.m., the group met with Amber Carran-Fletcher of the District Department of Transportation (DDOT) for a walking tour of the slug line locations on 14th Street. Carran-Fletcher detailed DDOT’s efforts to move some of the slug lines currently located on 14th Street to side streets to avoid the lane slowdowns that can occur when vehicles stop in a travel lane to pick up passengers. For many years, vehicles have stopped illegally along 14th Street to pick up slugs—enforcement was rather lax so it occurred “under the radar,” and citations were rarely issued, perhaps because commuter and local Metro buses also stop in the curb lanes in the same area to pick up passengers.

The scan group walked down 14th Street with Carran-Fletcher to the National Mall to visit DDOT’s new proposed slug line locations. Masoud Hamedi, a civil engineering student enrolled in a doctoral program at the University of Maryland, College Park, and who is interested in technology-facilitated dynamic ridesharing also joined the group (see figure 4). The afternoon slug lines are located on 14th Street. The slugs like to be able to see commuter bus stops from their line locations so that they can catch the bus if it arrives before a driver looking for a slug does.

A woman and three men are standing together in a parking lot. It is daytime, and the parking lot is surrounded by trees and grass; a red brick building can be seen in the distance. The woman is on the left, and she is talking to the man who is second from the right; the other two men are listening. It is a bright day: the woman and the man on the far right are both wearing sunglasses.

Figure 4. Amber Carran-Fletcher of DDOT, Masoud Hamedi of the University of Maryland, Patrick DeCorla-Souza of FHWA, and Peter Valk of Transportation Management Services Consulting (left to right).

On the afternoon of November 18, the scan group drove across the Potomac River to Virginia to meet with transportation-planning staff at the Pentagon and to learn more about the slug lines there. The tour was guided by two Department of Defense (DOD)–Washington Headquarters Services1 contractors who discussed how the slug lines function there and what the Pentagon does to help accommodate them. The Pentagon public works department provides signage that indicates to which destination(s) each slug line pertains. Facility planners there have also taken advantage of a former bus-queuing area with shelters and lots of curb space to accommodate several of the slug lines.

The Pentagon is the most popular morning slug line destination, has the most individual afternoon lines of any location, and also has the highest total slugging volume of any location. The group again interacted with slugs there and observed the slug lines but took no photos because of security restrictions. After spending approximately 2 hours observing the Pentagon slug lines, the group members lined up at the Horner Road slug line for the afternoon reverse commute and caught rides back to the Horner Road Park-and-Ride lot.

In the evening, the scan team reconvened to discuss the day’s observations and to meet with David LeBlanc. LeBlanc wrote the book Slugging: The Commuting Alternative for Washington, D.C. in 1998 and subsequently started the Web site www.slug-lines.com, which is a central information clearinghouse for slugging. As both a long-time slug and author, LeBlanc is an expert in the “operational” side of slugging and has used his Web site to help slugs with line information, discussion forums, lost-and-found postings, and promotions for new slug lines. LeBlanc said that he resisted slugging for a number of years before finally giving it a try. All it took was trying it once, and he was converted. Being frustrated by the lack of information on the subject, he decided to write the book to help provide information to slugs. The Web site was originally an afterthought to be used for marketing the book, but it has turned out to be the best asset for distributing information about slugging. LeBlanc’s Web site has more than 18,000 registered users (you must register to post on the message boards) and is also used to help create new lines or move the locations of existing lines.

The next morning, November 19, the scan group visited the slug lines at Potomac Mills Mall, a major regional outlet mall in Prince William County, VA, with easy access to Interstate 95 (I-95). For many years, Potomac Mills furnished about 1,000 parking spaces each weekday for commuter use, until March 2011 when that number was scaled back to 250 spaces to provide space for new construction at the mall. There were three individual slug lines at the mall that served downtown DC; Rosslyn, VA; and the Pentagon; one of these lines is shown in figure 5. The group again interacted with people in line and drivers of vehicles who were waiting to pick up slugs. The group asked the slugs questions, such as how they got started slugging and what it took for them to try it for the first time. Many people responded that a testimonial from a trusted co-worker or family member was one of the most popular ways to convince people to try slugging for the first time.

A daytime photo of a parking lot. Thirteen people are lined up on the left side of the photo in front of some parked cars. Beyond the parking lot are trees whose leaves have changed to fall colors. It appears to be cold: the people are all wearing coats, jackets, and sweat shirts. Three cars are driving up to the line of people from the right side of the photo, the first one with its headlights on.

Figure 5. Slugs lined up at Potomac Mills parking lot with vehicles approaching from the right side.

The scan members waited in the Rosslyn slug line and slugged individually to the Rosslyn destination in Arlington, VA. There they met with Peggy Tadej of the Northern Virginia Regional Commission and representatives of Arlington Transportation Partners to learn more about the commuting situation in the Northern Virginia region. The meeting focused on the effects of the DOD Base Realignment and Closure (BRAC) Act workforce movements happening in the area, their impacts on traffic, and how slugging might help. Afterward, the group had a meeting with a representative of AVEGO, a private firm that markets dynamic ridesharing software for smart phones (e.g., iPhone, Android, etc). The discussion centered on the possibilities for technology to help facilitate non-organic dynamic ridesharing in new locations and corridors.

Afterward, the team adjourned the Washington, DC, portion of the scan with instructions to reconvene 3 weeks later in Houston, TX.

Summary of Lessons Learned and Analysis of Practices

Slugging in Washington, DC, is unique for several reasons. The two dedicated (HOV) lanes along I-95 stretch for 43.5 km (27 mi) south of the city. Washington has, by far, the best information Web site (www.slug-lines.com) of the three cities, which does an excellent job of publicizing this commute mode.

The high number of unique origins and destinations in Washington, DC, is also of great interest. This probably has been facilitated by the existence of the slug line Web site, whereas other cities share information more so via word-of-mouth. The fact that Washington has so many Federal Government employees also may serve as a catalyst for slugging. These workers have regular, consistent work schedules and similar work situations (down to the identification badges that they wear around their necks), which probably helps increase the level of trust among participants.

General Observations

These general observations are largely based on the trip summary of scan member Phil Winters and others’ discussions with slugs in line on November 17 and 19. The key elements for slug line success appear to involve the following characteristics:

When discussing how slugs first heard about the concept of slugging, the following sources were frequently mentioned:

Individuals cited the following advantages to slugging:

Additional observations of the slug lines include the following:


1 Washington Headquarters Services is a DOD field activity that provides operational and support services to DOD tenants in the National Capital Region.


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