Traffic Operations Centers (TOCs) for Smaller Agencies: Colorado Example

Traffic Operation Centers (TOCs) have historically been built and operated by the Traffic Engineering Departments of state departments of transportation (DOTs) and larger cities. For example, in the Rocky Mountain region, the City and County of Denver, City of Lakewood, and Colorado DOT (CDOT) have highly utilized Traffic Operation Centers.

By contrast, smaller cities and agencies often do not have the means to build a TOC of their own, due to reduced manpower and budget.  As a result, smaller cities and agencies often cannot provide system monitoring, event management, crisis management, and advanced traffic control functions often provided through operation of a TOC.  The National Traffic Signal Report Card, Technical Report 2007, indicated that agencies operating small signal systems of fewer than 50 signals had lower performance than all other agencies, indicating that smaller agencies may benefit from the improved system performance made possible through a TOC operated by trained, experienced personnel.

In Colorado, several small agencies are gaining the benefits of a TOC within a manageable budget by contracting out for these services.  A private contractor may provide seamless support for local municipalities, even when budgets are adjusted or personnel moves occur that might otherwise adversely affect an agency’s ability to fully manage a TOC.  When new agencies are formed for which a TOC may prove beneficial, a private contractor, with the necessary hardware, software, and agreements in place, may provide start-up support as requested. As an example, W.L. Contractors Inc., provides monitoring or management services and operates a privately owned TOC that serves the following municipalities in Colorado:

1. Adams County, CO

2. Arapahoe County, CO

3. Arvada, CO

4. Black Hawk, CO

5. Castle Rock, CO

6. Centennial, CO

7. Commerce City, CO

8. Jefferson County, CO

9. Lafayette, CO

10. Littleton, CO

11. Louisville, CO

12. Northglenn, CO

13. Superior, CO


Greater Denver Area Public Agencies with System Monitoring Operated by W.L. Contractors, Inc. (located in Arvada, CO)

The system operated by W.L. Contractors in Colorado provides an example of how a privately operated TOC can benefit smaller municipalities and transportation agencies.  For other municipalities or agencies that may seek to follow a similar model, this article describes the types of services offered.

Available System Software:

The TOC managed by W.L. Contractors, Inc. incorporates closed loop traffic system software packages commonly used by our customers throughout Colorado. Connections to closed loop system master controllers is commonly established through the use of dial-up POTS connections.  For agencies which have established centralized type traffic systems, I.T. Department approved remote access may be required and may be established through a Virtual Private Network (VPN) or remote terminal access.


The services provided for each agency differ depending on the contract.  Several factors, including the availability of agency personnel and the agency personnel’s system comfort and understanding, determine the role that the private contractor plays in setting up and maintaining the TOC.  The contractor provides the system understanding, expertise, personnel, and technology needed to identify and prioritize issues as they arise.  When necessary, the contractor provides repair personnel as well.  Some of the services offered are described below.

System Monitoring: Daily Communication Checks

Since a system provides value to an agency only when functional, the contractor performs communication checks to each signal on a daily basis to check for errors. In the event of failed communications, operators at the TOC quickly dispatch repair crews.  When communication failures result from a third party’s operations, repair crews can often identify the responsible party, record pertinent information, and provide documentation to the appropriate agency for follow-up as required.

Daily, the TOC performs program comparisons between the stored database and active programs in the field.  When database differences are noted, the TOC operators often can  identify who made the changes and for what purpose, and verify the effectiveness of the database change. When invalid database modifications are detected, such as may occur as a result of controller EPROM malfunctions, operators restore the database and notify agency representatives.

Automated time sync to WWV

Master controllers clocks are synchronized to WWV to maintain proper coordination throughout the system and with adjacent agencies, on a daily basis or more frequently when required.

Automated reporting

The contractor uses automated notification procedures throughout both the monitoring and alarm notification stages to maximize effectiveness while reducing costs to customers.

Remote plan review and implementation

With the employment of engineering, technical, and maintenance staff, the contractor may bring a high level of expertise to the table for timing plan review and implementation services.  With the knowledge gained from monitoring and/or collecting data at an intersection included in the TOC’s network, the contractor can identify conflicts and concerns prior to implementation to reduce an agency’s liability. The contractor may complete implementation through the TOC to maximize effectiveness while reducing costs to customers.

When changes are implemented through  use of the TOC and remote communications, timing implementation can be completed quickly and accurately, resulting in limited liability that may otherwise result from delayed response. Reduced costs are realized as mobilization charges are not applicable.

Equipment! The Backbone of the TOC

Equipment! The Backbone of the TOC

Limitation of emergency liability:

During an emergency, the contractor can respond quickly from the TOC, with remote access to the agency’s traffic signal system. Such emergencies may include blizzards when visibility is low; road markings and other traffic control devices often cannot be seen. In such instances, TOC operators may place signal phases on vehicle recall to ensure all phases are provided with adequate green time. Signal adjustments such as these may limit an agency’s liability during an emergency or other incident.

Event management:

The contractor may provide customized event management services to aid in traffic ingress and egress.   A multi-agency corridor wide plan review is often completed prior to the event based on realistic anticipated traffic volumes, traffic patterns, parking restrictions, and planned police department involvement.   During the event, TOC staff members, including contractor staff, monitor event ingress and egress with the use of CCTV cameras installed throughout the corridor.  During monitoring operations, TOC staff members remain alert for accidents and incidents which could impede progress; response personnel are dispatched as required.  Event response by attendees may vary from what was anticipated, based on weather conditions and/or attendee interest. TOC staff members are available to adjust timing plans as required to meet current event demands throughout the event.

Additionally, during the event, contractor technicians are located throughout the corridor to provide quick response to traffic signal failures that would otherwise impede the flow of traffic.

Contract management:

Using system logs, the contractor can determine the time at which a system failure occurred and the time at which the controller cabinet door was opened by the responding technician intending to make repairs.   These data are required for public agencies needing to determine if technicians are adhering to contract-defined response times for traffic signal failures.

Traffic volume comparisons via system loops:

When systems are set up such that traffic volumes are being recorded, remote communications permit the TOC to store system logs so that comparisons may be completed on a regular basis.  As traffic volumes increase, the contractor assists the agency in determining when the effectiveness of a coordination plan is reaching the end of its life cycle, and when a corridor coordination study may be required.

Database redundancy

When closed loop systems are used, the TOC provides database redundancy for agencies.  If the agency’s system server fails, the contractor provides interim services as needed until repairs are made.  Support is seamless and provides for continued service to the public.

Customer reporting:

The contractor generates reports on a daily basis to keep the agencies informed throughout the term of service.  The reports help minimize the agency’ liability as they show adherence to safety standards for the public and compliance with the agency’s specific requests.

TOC Facilities Maintained by W.L. Contractors, Inc., in Arvata, CO, for Counties and Municipalities in the Greater Denver Area

TOC Facilities Maintained by W.L. Contractors, Inc., in Arvata, CO, for Counties and Municipalities in the Greater Denver Area


While technology within the traffic signal industry continues to evolve, W.L. Contractors, Inc. has been instrumental in detailing and staging system upgrades for many agencies throughout Colorado to support this evolution.  The contractor has been instrumental in providing agency-wide system designs and defining system component specifications. System designs have supported the use of copper, fiber, and/or wireless interconnect, and associated hardware, for use in both centralized and closed loop traffic systems.  Where funding has permitted, and where feasible, ethernet technology has become a standard for many of the designs.

W.L. Contractors, Inc. assists agencies in monitoring and managing their existing systems; both closed loop and centralized.  Public Works Departments are recognizing the benefits of these services.  Where required, and although I.T. Departments are hesitant about providing access through fire-walled networks, Public Works Departments, I.T. Departments, and W.L. Contractors, Inc. can often work together to define policies and procedures, and resolve the issues.

Partnerships for contracting out TOC services may be feasible for agencies that already have systems in place, as well as new developing agencies in need of assistance.  Where new agencies are being formed, construction standards may not be fully defined and often, agencies feel it is not the right time to make hardware decisions.  However, by defining system hardware specifications early on, cost may be greatly minimized.


Private companies may encounter limitations when it comes to the monitoring, managing, and supporting of agency systems.  Challenges for private contractors include limited permission to access networks or data and the limited availability of bandwidth. As technology continues to improve, public-private partnerships for installing, staffing, and maintaining Traffic Operations Centers are expected to become more common.  In this way, private contractors can help smaller municipalities and agencies increase the efficiency of their transportation systems without incurring the large price tag of operating their own independent TOC.

About the Authors

Tim March
Tim March has been working in the traffic signal industry since 1988 when he started with the New Jersey Department of Transportation.  His training and experience as an electronics technician in the US Navy allowed him to quickly grasp traffic signal technology.  In 1999 Tim was hired on at WL Contractors, Inc. where in 2002 he assumed the role as Technical Manager.  In 2004, Tim earned his degree in IT from the University of Phoenix and continues to embrace newer technology and realize its uses in today’s traffic management market.

Michael Schmidt

Michael Schmidt is General Manager of W.L. Contractors Inc. He has been in the Electrical field for 40 years and the Traffic Signal Industry since 1989.  Mike is a Master Electrician and a sustaining member of IMSA. He has a BA from Tennessee Temple University and an MBA/Technology Management from the University of Phoenix.

W.L. Contractors Inc.

5920 Lamar Street

Arvada, CO 80003


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