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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - Winter 1995

The Safety Challenge: The National Capital Beltway

by Ilona Orban

This article is an update to the article on Capital Beltway safety in the Summer 1994 issue of Public Roads.


The Capital Beltway Safety Team recently announced 13 actions to improve safety on the 101-kilometer highway that rings the nation's capital. The team conducted a press conference and publicly released the Capital Beltway Safety Update report Sept. 29, 1994, at the Turner-Fairbank Highway Research Center in McLean, Va. National, state, and local legislators and transportation officials were present at this major milestone in the continuing effort to improve safety for the Capital Beltway, often referred to as "the main street of the nation's capital."


The Capital Beltway is a 101-kilometer interstate highway that rings Washington, D.C.


Any action affecting the beltway is complicated because coordination is required among two states, the District of Columbia, several counties and cities, and the federal government. As Federal Highway Administrator Rodney E. Slater noted, "This effort is a model for regionwide cooperation that applies to facilities across the nation that face similar challenges."

With the release of the Safety Update report, the move toward a safer beltway enters its third phase. In the first phase, August to December 1993, 53 safety recommendations were generated. In the second phase, January to September 1994, these recommendations were analyzed and evaluated, additional research was conducted, and 13 action items were developed. The Capital Beltway Safety Update with more than 350 pages contains all work completed in this second phase. During the third phase, currently under way, the analysis of problem areas will be expanded, and specific corrective and preventive measures will be implemented.

This article focuses on the second phase.

The Capital Beltway Safety Team

In January 1994, the Capital Beltway Safety Team was formed with Tom Farley, Northern Virginia District administrator of the Virginia Department of Transportation (VDOT), as its leader. To move the effort forward, the transportation and enforcement agencies that play major roles in operating the beltway formed a core group with representatives of VDOT, Virginia State Police, Maryland State Highway Administration (MDSHA), Maryland State Police, Council of Governments, District of Columbia Department of Public Works, Federal Highway Administration (FHWA), and National Highway Traffic Safety Administration (NHTSA).

At the outset, the team realized that it needed more concrete information to identify, develop, and implement countermeasures to improve safety. To support the team's efforts, the NHTSA and FHWA sponsored several studies to better understand beltway problems. These studies were performed under contract by research firms and institutions to analyze drivers' attitudes and behaviors, traffic and crash characteristics, and the 53 recommendations.

Beltway Driver Focus Groups

The nine focus groups of car and truck drivers who regularly use the beltway provided the following opinions of the problems they experience on the roadway:

  • Congestion is the number one problem on the beltway.
  • Dangerous driving behaviors of other drivers -- speeding, excessive lane changing (crossing multiple lanes and cutting off drivers), and driver inattention (talking on car phones, reading) -- are the most important safety problems.
  • The shared acceleration/deceleration lane, a design feature of full cloverleaf interchanges that forces entering and exiting traffic to merge within a short distance, is the most important design problem.

With many other recommendations, the focus groups placed highest priority on four actions to correct beltway problems:

  • Increase enforcement to curb the driving behavior problem.
  • Improve interchange operations.
  • Segregate roadways for trucks and vehicles. This was well-received by car and truck drivers.
  • Provide better signing and real-time information.

Results of Studies

The major findings of the crash and traffic pattern analyses can be categorized as beltway crashes, tractor-trailer crashes, and fatal crashes.

Beltway crashes

  • As could be predicted, the peak time for crashes coincide with rush-hour congestion.
  • Congestion caused by a single crash contributes to subsequent crashes.
  • Rear-end collisions are 44 percent of all beltway crashes. The principal causes are following too closely, driver inattentiveness, and differential speeds. In most cases (73 percent), the lead vehicle slowed or stopped because of traffic congestion.
  • About 22 percent of all crashes are the result of a vehicle leaving the road and striking an object or overturning. This crash type typically involves a single vehicle and often occurs late at night.
  • Approximately 17 percent of crashes occurred when one vehicle sideswiped another. This crash type is typically related to congestion or frequent lane changes.
  • More crashes occur on Friday than any other day, and more crashes occur in November and December than in other months.
  • About 8,000 trucks use the beltway daily; peak use is at noon. Vehicle miles of travel are increasing, but the accident rate per 100 million vehicle miles has actually decreased from 100 to 70.
  • There are a significantly higher number of accidents at 27 locations -- all at or near interchanges. Nearly 44 percent of all crashes and 48 percent of sideswipe/cutoff crashes occur at these locations, where lane changes are frequent.
  • Most drivers (83 percent) in beltway crashes are local residents.
  • One-third of crashes occur on wet, snow-covered, or icy pavement.

Tractor-trailer crashes

Trucks -- tractor-trailers and single-unit trucks -- account for about 10 percent of beltway traffic, but they are involved in about 20 percent of the crashes. More than half (51 percent) of crashes involving tractor-trailers are sideswipe/cutoff crashes. Location and familiarity with the roadway play major roles in tractor-trailer crashes. About 70 percent occur on the I-95 section of the beltway. Only 34 percent of tractor-trailer drivers are based in the Virginia-Maryland-District of Columbia area as compared to 86 percent of other vehicle drivers.

Fatal crashes

A comparison of fatal crashes on the Capital Beltway to fatal crashes on 20 major metropolitan beltways revealed that the Capital Beltway has:

  • More rear-end crashes, but much fewer head-on crashes (1 percent vs. 8 percent).
  • Fewer alcohol-related crashes (11 percent vs. 25 percent).
  • More tractor-trailer crashes (18 percent vs. 9 percent).


At a press conference Sept. 29, 1994, Tom Farely, chairman of the Capital Safety Beltway Team announces the 13 action items developed by the team to improve safety on the beltway.


Aerial Surveys

The Washington Council of Governments (COG) Transportation Planning Board supported the Capital Beltway Safety Team by sponsoring two aerial survey programs. One focused on peak-period, recurring congestion and the other concentrated on nonrecurring, incident-related congestion.

Aerial photos taken during the morning and afternoon peak periods identified the locations and nature of recurring congestion. The Safety Team has started to link congestion information to crash analysis results.

The aerial survey of nonrecurring, incident-related congestion is part of COG's ongoing freeway congestion monitoring program. Photographs of congestion relating to incidents at several time intervals will provide insight into how congestion builds up and dissipates. About half of the surveyed incidents on the beltway had a secondary incident in the backup caused by the primary incident. This points to the need to improve incident response time to reduce delay, related congestion, and secondary incidents.

Implementing Priority Actions

Ongoing actions

By the September press conference, several actions had already been initiated by team members. Some of these actions are:

  • Maryland and Virginia conduct late night patrols to target drivers who speed, tailgate, or park illegally on the shoulders of the beltway.
  • Maryland and Virginia have several programs, projects, or practices that target speeding and mechanically unsafe trucks.
  • A special nine-member, multidisciplinary crash team now investigates major beltway crashes.Trucks are prohibited from using the left lane for the entire length of the beltway.
  • Maryland and Virginia instituted a free, #77 cellular phone service so motorists can report disabled vehicles and other nonemergency traffic disruptions.
  • The beltway safety jurisdictions now coordinate and cooperate much more closely on all aspects of beltway safety and operations. A quarterly newsletter is distributed to more the 800 national, state, and local legislators; members of public and private organizations; and citizens concerned about beltway issues.
Variable message signs provide important information to motorists. In this case, the message provides drivers in congested traffic some advanced warning that traffic ahead will be merging in the center and left lanes.


Safety team's 13 action items

A highlight of the September Safety Update event was the announcement of the Capital Beltway Safety Team's 13 priority actions. Six of the actions target improving drivers' behavior, and six are engineering improvements. One action item focuses on sustaining this safety effort. Some of the action items have been adopted -- partial funding is available and implementation has begun. Others are under development -- necessary steps toward implementation are being identified. The 13 action items are:

  1. Increase Enforcement (under development). Maryland and Virginia should increase enforcement to control speeding and aggressive driver behavior.
  2. Increase Points and Fines (under development). Maryland and Virginia should reevaluate their point and fine systems. Raising points and fines will bring them to current levels in surrounding states.
  3. Implement "Drive to Survive Together" (adopted). MDSHA and VDOT will implement "Drive to Survive Together," a program to improve driver performance and behavior.
  4. Implement the Automated Speed Monitoring and Warning Program (under development). More efficient and cost-effective traffic-monitoring techniques are needed because traditional methods are inadequate.
  5. Provide Enforcement Areas (under development). Maryland and Virginia will identify as many as four sites in each state to provide additional areas along the beltway for enforcement and accident investigation activities.
  6. Enhance Work Zone Safety (adopted). Problems associated with construction are congestion caused by lane closures and speeding when traffic flows freely. To control speeding, radar and variable message signs will warn drivers of their speeds and the fines associated with them.
  7. Improve Interchange Operations (under development). The Maryland-Virginia Design Team has developed three possible options to address this problem. Before constructing any of the options at specific locations, computer simulation, evaluation, and comparison will be completed, along with a crash analysis.
  8. Improve Highway Signing (adopted). A bi-state team on signing examined existing signs for message content, quality of material, letter size, and the use of overhead guide signs. This study identified the need for uniformity, a review of all nonessential messages, and a systematic program for sign replacement. The team is pursuing ways to improve accurate real-time information on variable message signs.
  9. Implement Intelligent Transportation System (ITS) Strategies (adopted). Implement the latest ITS strategies and devices to improve operations, increase vehicle safety, and lessen congestion.
  10. Expand Regional Incident Response Training (adopted). Develop regional, incident response training for highway, police, and fire and rescue personnel.
  11. Enhance Pavement Markings and Other Delineations (adopted). Maryland and Virginia will use high-quality material (thermoplastic quality or better) to ensure uniform markings for ramp, weave, merge, and acceleration/deceleration areas.
  12. Upgrade Beltway Lighting (adopted). Virginia and Maryland are addressing the definite need for additional lights as well as upgrading existing equipment.
  13. Sustain High-Level Focus on Safety Through Cooperation and Interaction (adopted). The partners in the Capital Beltway safety effort will continue to conduct a multijurisdictional, regionally coordinated approach to problem solving.


When traffic on the beltway is at virtual standstill, the traffic on feeder roads quickly backs up. This situation also increases the danger of an accident in the acceleration/ deceleration lane, where traffic entering and exiting the beltway must merge.


The Future

"I am proud of the accomplishments of the Capital Beltway Safety Team and honored to have been involved in the progress," said Farley. "Our success is the result of assuming ownership of beltway problems and the unswerving focus on safety, which has provided the common link among varied, often opposing interests. The broad-based participation ensured a regionwide perspective. Our commitment to include public and private participation provided an effective partnership to identify problems and their solutions. In a sense, however, our job is just beginning. We are assimilating information and are challenged to implement the action items. But we have formed the relationships that are vital to the future of the Capital Beltway and the safety of those who drive it."


Capital Beltway Safety Team. Capital Beltway Safety Update, Fairfax, Va., Sept. 29, 1994.

Ilona Orban is a transportation engineer at VDOT's Northern Virginia District Office in Fairfax, Va. She is the project coordinator of the Capital Beltway Safety Team and has been with VDOT for four years. She received a master's degree in transportation systems engineering from the University of Technical Sciences of Budapest in 1981 and is currently completing a master's degree in civil engineering at the University of Virginia.