Closed Circuit Traffic Monitoring

Closed Circuit Traffic Monitoring

In conjunction with the computerized signal interface, the traffic operations center is equipped with 19 closed circuit television monitors, which are connected to on-street cameras located on the arterial routes. The cameras assist the traffic staff in recognizing traffic problems and making remote timing changes via the interconnected traffic signals to help in maximizing the efficiency of the on-street traffic flows.

In early 1994, the city approached FHWA and TDOT with a plan to establish Closed Circuit Traffic Monitoring (CCTV) to supplement the city's existing system. The basis of the city's proposal was to install CCTV cameras along four arterial routes and one future route to provide complete visual coverage within the visual limits of each signal. This would eventually provide coverage of about half the city's entire primary arterial roadway network.

Congestion Mitigation and Air Quality Improvement (CMAQ) funds were proposed to underwrite the project and, because it was the first CCTV system in the state, FHWA and TDOT funds were considered critical for the project which would maximize both the efficiency of each arterial route intersection and overall flow through each of the signals involved. Both agencies were very supportive.

During the design phase of the project, communications were the primary focus and various technologies were researched. After an extensive analysis, use of fiber optics was considered the most cost effective and technologically advantageous option considering existing needs, future expansion needs and incorporation of other Intelligent Transportation Systems (ITS) traffic management components such as variable message signs, highway advisory radio, real time street conditions based on street sensor feedback and integration into a regional traffic management center.

The City of Murfreesboro contracted with two firms to separately design two phases of the project. They wrote specifications for fiber optic cable type and capacity, cameras, the traffic operations center and on-street hardware and control equipment. The designs also included on-street cable routing plans for each corridor including overhead pole attachment locations and underground routing as well as other design elements. Phase One of this bid-ready document was completed in February of 1997 and Phase Two was completed in September of 1999.

The original phase one project consisted of the installation of approximately seven miles of fiber optic cable interconnecting 13 cameras along four distinct primary arterial routes. The traffic signals along these routes had been previously interconnected since 1987 with twisted pair copper wire communications. The camera installation provided visual monitoring of 24 high volume signalized intersections along these routes. The process included installation of fiber optic cable and permits from TDOT and CSX railroad to use their rights-of-way were required. Because federal funds were involved, an environmental assessment was also required.

The first phase was bid in March of 1997, awarded to the low bidder for $468,000 and the construction completed in July of 1998.

The second phase included installation of approximately four miles of fiber optic cable interconnecting six cameras along one arterial route to provide visual monitoring of five existing signalized intersections. Three additional installations were scheduled. The project required the same permits and environmental assessments as for the first phase. Phase Two included interconnection of the traffic signals along this corridor.

Phase Two was bid in October of 1999, awarded to the lowest bidder in November for approximately $360,000 and was completed in May the following year.

We hope to retain and maximize this visual information and system effectiveness that formed the desire to incorporate CCTV technology into the city's existing traffic operation and management scheme. The strategic manipulation of system timings has many advantages such as reduced travel time, reduced stops and reduced stopped delay as well as air quality benefits derived from these reductions.

Many other transportation related uses have been realized through the use of visual information relayed from closed circuit television. Some of these uses are listed as follows:

  • Visual verification of reported signal malfunctions-allows verification of malfunctions prior to dispatching signal crews.
  • Visual verification and identification of congestion reported via system sensors
  • Incident Detection - allows for quick and correct dispatch of emergency personnel and provides basic building block for later incorporation of incident management system.
  • Allows for remote traffic counting capability - Turning Movement, Volume, Occupancy and other traffic information can be collected from the central control room deleting the necessity to field locate personnel.
  • Delayed traffic counting capabilities - Allows for recording of traffic conditions, which can be tabulated at a later date as time permits.
  • Identification and/or confirmation of missing traffic control devices.
  • Evaluation of needed improvements to pavement and pavement markings.
  • Roadway drainage deficiencies.
  • Time savings provided by the ability to view more than one location at one time.

Murfreesboro has completed two phases of approximately 11.5 miles of fiber optic cable interconnecting 19 cameras and five traffic signal controllers. Thirteen camera monitors and the computerized traffic signal interface are housed at the city's traffic operations center at City Hall.

In addition to the every day use of the systems enjoyed by the traffic staff, the city transmits live video in the AM and PM peak traffic periods over the government Cable Channel 3. This effort was supported in an attempt to provide the motoring public travel information that can be used in making informed travel decisions.

Approximately 94 percent of the project's $900,000 development cost, including engineering and construction, was federally funded.

The incorporation of CCTV into the city's traffic management scheme has been a success and has achieved national recognition. Murfreesboro's city council and administration recognize that high growth within the city, and the increased traffic that results, requires large but prudent expenditures of capital including relatively low cost efforts to maximize the efficiency of the existing roadway system.