Traffic Engineering

The Traffic Engineering Division, which is located at 2900 Business Center Drive, provides and maintains a comprehensive City-wide traffic signal system that includes the traffic computer system linking many of the City's signaled intersections.

Page updated on Apr 26, 2018 at 9:04 AM

Traffic Signal Picture (web page)

Mission, Vision and Values


The Traffic Engineering Division’s mission is to provide improved mobility in Alexandria and the region through sound engineering, design, technology implementation, and regional cooperation.


The Transportation Division is a proactive and effective organization with drive for innovation.


  • Always incorporate the best solutions in the industry

  • Always base decisions on well-founded engineering and research

  • Always value teamwork and open communication

  • Always serve the public with dignity and respect

  • Always seek and look ahead for innovative technology and ideas

  • Proactively adapt to changes to better serve the community and region

What’s new?

  • fuel cell 1Hydrogen Fuel Cell Traffic Signal Pilot: Alexandria is the first city on the East Coast to use a hydrogen fuel cell as a backup power source for traffic signals. In the summer of 2017, the Department of Transportation and Environmental Services modernized the intersection that connects King Street, Quaker Lane and Braddock Road with the installation of a hydrogen fuel cell backup generator, among other improvements. The fuel cell turns on the instant that utility power fails and allows the traffic signals to remain in operation without interruption, which helps prevent crashes during power outages. The cells are a green technology and offer better cost savings and reliability and less maintenance than  traditional battery backups. The installation is part of a pilot project--the King/Quaker/Braddock intersection was chosen because it serves roughly 3,500 vehicles per hour during peak periods. As fuel cell costs continue to decrease and the technology becomes more common, the City expects to expand the pilot to additional intersections over the next several years.

  • Adaptive Traffic Signal Control System Grant: The City received a grant for the design and installation of a real time traffic adaptive traffic signal control system.  Most signal systems in the United States are not traffic adaptive and rely on fixed coordination plans to synchronize the signals. This scheme works similar to a programmable thermostat, in the morning the inbound coordination plans are activated and in the evening the outbound plans are activated based on a time clock regardless of actual traffic demand.  Under the Traffic Adaptive scheme, the system constantly monitors traffic flow and continually makes adjustments to traffic signal operation to optimize traffic flow. 

Traffic and Parking Board

All matters concerning traffic, parking and taxicabs are presented to the Traffic and Parking Board for consideration prior to action by the Director of the Transportation and Environmental Services Department or presentation to City Council.  The Board investigates, studies and analyzes traffic and parking problems within the city, receives complaints having to do with traffic and parking matters, devises plans, methods and means to control and relieve parking and traffic congestion, have jurisdiction over taxicabs and buses and their owners and operators, control parades within the City, prepare reports on traffic, parking and taxicabs, and render advice and make recommendations to the City Manager, the Planning Commission and City Council.  The Traffic Engineering Division prepares the Traffic and Parking Board dockets and manages the meetings.

Taxi Cabs 

The Transportation Division works hand in glove with the Police Department’s Hack Office to regulate the City’s taxicab industry.  The Transportation Division ensures a well running taxicab industry by conducting the biennial review where rate and code changes are made, developing City regulations and working with the taxicab companies.

Traffic Operations Center

The Traffic Engineering Division operates the City’s Traffic Operations Center.  The Center uses technology to consolidate and improve operations throughout the City.  Critical events such as snow removal, weather related operations and other special events as well as day to day operations are managed from the center.

Features include:

  • A broadband fiber optic communications network.
  • Traffic cameras.
  • Distributed traffic signal control
  • Deployment of AVL technology on vehicles.
  • Transit signal priority

Traffic Signals

Traffic signals can improve safety for pedestrians, bicycles and motorists as well as provide orderly movement of traffic when designed and installed properly Signals that are installed when no legitimate need exists can increase vehicle stops, traffic delays, fuel consumption, crashes and breed disrespect for other traffic signals.

Installation of traffic signals is preceded by a thorough engineering study. The U.S. Department of Transportation Federal Highway Administration has published the Manual on Uniform Traffic Control Devices, which contains the standard guidelines for all traffic signals in the United States, including City of Alexandria.

Traffic Cameras

Closed-circuit televisions (CCTVs), or traffic cameras, are used throughout the City to detect congestion, identify crashes and other incidents. There are currently 12 CCTVs located at critical intersections. This number will increase to more than 30 CCTVs during the final phase of the Fiber Optic Network Project.

HAWK Beacons

A HAWK Beacon (High-intensity Activated CrossWalK) is a device that assists pedestrians and bicyclists safely across busy streets. While different in appearance to the driver, to the pedestrian or bicyclist HAWKs work the same as button-activated traffic signals. It stops traffic with a red light allowing pedestrians and bicyclists to cross safely. At rest, HAWKs remain dark. HAWKs can be triggered automatically or manually with a push button. It will then go through a series of yellow and red sequences requiring motorists to slow down and stop. After pedestrians and bicyclists cross, the HAWK will go dark again, allowing motorists to continue through the intersection.

Accessible Pedestrian Signals

Accessible pedestrian signals are installed as the standard at all new traffic intersections in City of Alexandria. Requests for accessible pedestrian signals at older locations should be made to 703-746-4142. 

Completed Projects 

Ongoing Projects

  • Transit Signal Priority

  • Intelligent Transportation Systems

    City Staff Contact

    Cuong Nguyen, Traffic Engineer I, Department of Transportation and Environmental Services - 703.746.4142, or emails: