Systems Operations Program Area

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Operational Scenario

It's 5:00 PM on a Friday and westbound traffic on the SR-267-Dulles Toll Road (DTR) leading out of the Washington, D.C area is heavy. A few moments ago, a passenger car and semi-tractor trailer carrying furniture collided while passing beneath I-495. The car came to rest in the outside travel lane and the truck careened off the right shoulder and smashed into one of the support columns for the overpass. Traffic immediately comes to a stop in the two outside lanes and slows to a trickle in the inside lanes. Within minutes, the traffic back-up extends approximately two miles to I-66 and traffic flow on I-66 begins to slow.

Within moments of the collision, system operators at the VDOT NoVA Smart Traffic Center (STC)-which is responsible for operating the Dulles Toll Road-begin receiving notifications of the incident from the local 911 center (via Fairfax CAD), which has received cell phone calls from travelers; from one of their own Safety Service Patrol (SSP) operators who has come upon the incident scene; from Dulles Toll Road administration building staff; and from their traffic detectors in the roadway which flag sudden slow-downs as potential incidents. The STC operators spring into action, immediately:

Entering the incident into their incident database from which the information passes to the Regional Integrated Transportation Information System (RITIS), which provides access to the information by regional and local transportation and emergency coordination organizations, including CapCOM (Capitol Region Communications and Coordination Center) and to the Virginia Operations Information System (VOIS), a state-wide information sharing system.
Zooming in on the scene using a closed-circuit television (CCTV) traffic surveillance camera installed along the roadway to verify conditions
Establishing communication with appropriate state and local police and fire responders who have access to the CCTV images and whose computer-aided dispatch (radio) systems automatically display the incident database record input by the STC; from the STC automatically appears in the responders' computer-aided dispatch (radio) systems
Alerting the VDOT Smart Traffic Signal System (STSS) operators of the incident with whom they share space in the Public Safety Transportation Operations Center (PSTOC)
Dispatching VDOT maintenance staff to the incident scene to assist in debris removal and to investigate possible damage to the overpass
Alerting the operators of the DTR toll system to lift the toll until the incident is cleared in order to facilitate traffic flow
Alerting the operations center of the transit agency that operates buses on the shoulders of the DTR.

Using their automatic vehicle location system, the STC operators are able to quickly determine that a second SSP vehicle is near the incident scene and dispatches them to the area. The en-route and on-scene SSP operators are able to gain a quick understanding of the overall incident scene by accessing CCTV images and talking to STC operators and as they gather information on-site they add it, via laptop computers and wireless communications, to the incident database record created by the STC, making up-to-the-minute information available to all those with access to the incident record. As the SSP arrives on the scene, STC operators ask SSP to take a picture of the damaged structure on which the control room CCTV could not have a clear view. SSP take the picture, record a voice message on the initial assessment, and send it to STC.

Upon verification of the incident scene and traffic impacts, the VDOT STSS operators put into place a traffic diversion plan. That plan includes close coordination with the STC staff responsible for activities on the DTR and implementation of a special, pre-defined traffic signal timing plan for signals on the adjacent arterial streets that will carry much of the diverted DTR traffic. STC operators then communicate with SSP on-scene to direct traffic to the adjacent arterial streets and coordinate Area Headquarters maintenance staff to assist deploying traffic cones to guide the diversion traffic.

By 6:30 pm, backups extend to the 14th Street Bridge as first responders (police and fire) conclude their investigations and work begins on clearing the incident. Realizing that the incident is now beginning to affect operations on roadways operated by other jurisdictions, CapCOM operators alert DC traffic operators, Maryland CHART, and GW Parkway operators so that appropriate message can be posted onto electronic Variable Message Signs in DC and Maryland for travelers to avoid getting onto I-66 that leads to DTR.

In addition to the many immediate actions taken by the STC to involve and coordinate with those agencies responsible for clearing the incident and managing traffic, a number of actions are taken to advise travelers of the incident, including:

The STC posts messages on several roadside electronic Variable Message Signs (VMS) on several roadways impacted by the incident, including the DTR, I-495 and I-66
The STC relays incident information to several commercial media outlets for their dissemination to travelers
Drawing on the incident information entered by the STC into the VOIS, the Virginia 511 state-wide traveler information system posts advisory messages on their website (511virginia.org) and telephone information system.

Travelers at various locations and in various stages of their trip can access these various information sources to learn about the DTR incident and adjust their plans accordingly. Commuters hearing about the incident via commercial radio or 511 Virginia could choose to postpone their departure from work or to plan an alternate route or even switch to transit. Drivers on roadways several miles upstream of the incident seeing VMS messages or hearing traffic radio reports could choose to stop off and run errands, allowing time for the incident scene to clear, or could detour to an alternative route. Even those motorists close to the incident scene and having few options other than waiting it out will value the incident information made available to them. The information can help reduce their sense of confusion and frustration and may at least allow them to adjust their travel time expectations, and increase their awareness and caution as they pass through the congested area, including the incident scene itself.

At 7:00 pm, all lanes on DTR are open to traffic. After the incident is cleared, the traffic congestion lasts another hour. Therefore, the STC operators adjust messages to the travelers urging caution driving through the congested area and understand the reason of abnormal traffic condition.

Tier II - Activity Areas:

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