The department's Transportation Improvement Program (TIP) is a statewide plan that sets priorities for major transportation projects. Plans, specifications and estimates for traffic signal work may be part of the TIP. The traffic signal plans, specifications, and estimates developed for the TIP are incorporated into the overall roadway project plans for letting a contract by Design Services. This may include requirements for temporary and permanent traffic signal installations. Construction requirements on TIP projects may require the extensive use of temporary traffic signal configurations to accommodate proposed roadway widening, proposed lane configuration changes, or the use of temporary haul roads for construction equipment. To determine the need for temporary signal configurations and to assist in developing the construction phasing, extensive coordination must be maintained with the Traffic Control, Marking, and Delineation Section. Assistance is also provided to the Resident Engineer during construction of the traffic signal installation.

Plans, specifications and estimates for traffic signal work may also be prepared as part of the Spot Safety Program or the High Hazard Elimination Program. These programs were established as a means for the department to respond quickly to identified transportation improvement needs necessary to alleviate traffic congestion and improve safety. Traffic signal plans, alleviate traffic congestion and improve safety. Traffic signal plans, specifications, and estimates prepared under these programs have short, critical deadlines. Deadlines for Spot Safety Program projects are incorporated into the Tip. In order to properly engineer necessary traffic signal or intersection geometric improvements on these projects, stadia surveys of existing field conditions must often be performed and extensive coordination must be maintained with the Traffic Field Operations, Investigations, and Support Section.

Traffic demands at signalized intersections may change over time. New developments or residential areas may increase traffic demands at a particular location; whereas, opening new roadway routes may decrease traffic demands at other locations. Though modern traffic signal equipment may have the ability to make "on the spot" adjustments to the green display times, limitations of the equipment still make field observation and adjustment of the timing parameters and traffic patterns at signalized locations critical to maintaining the most efficient, safest operation possible. The Signals and Geometrics Section prepares fully engineered plans for improving timing parameters and traffic patterns, installs these plans, and makes field adjustments based on actual observation of traffic flow. These adjustments often require independently made, good, solid engineering reasoning and judgement as they are typically made in the field while traffic is traveling on the roadway. Plans, specifications, and estimates prepared under the Traffic Signal Timing Program may involve signal systems for corridor closed loop projects as well as isolated traffic signal installations and time-based traffic signal systems. Traffic modeling computer programs are heavily utilized in preparing signal timing and traffic pattern improvements.

The Section reviews and approves all preliminary and final municipal and developer prepared plans, specifications, and estimates involving traffic signal work on the State Highway System. New developments such as shopping centers or industrial complexes can have dramatic effects upon traffic volumes and patterns along a roadway network. These effects may require the installation of a new traffic signal on the State Highway System. The plans, specifications, and estimates for these new signals may be financed by the developer and prepared by the Signals and Geometrics Section or a private engineering firm (PEF) hired by the developer. In order to protect the public and promote efficient signal operation along the State Highway System, the Signals and Geometrics Section is responsible for approving the plans, specifications, and estimates prepared by PEFs for required signal work. New traffic signals may also be required within an existing citywide traffic signal system. The Signals and Geometrics Section is responsible for approving all plans, specifications, and estimates for signal work along the State Highway System performed and authorized within a city-wide traffic signal system. Close coordination is maintained with the municipality to ensure successful completion of these new traffic signals.

The Signals and Geometrics Section provides analyses of intersection capacity when requested by the Roadway Design Unit, the Design Services unit, or Divisions. The Section performs intersection capacity analysis using various traffic simulation computer software programs for proposed projects. These analyses identify possible capacity deficiencies involving such items as turning lane storage capacity, number of lanes for movements, and intersection delay. The Section performs interchange analysis to determine the adequacy of interchange proposals for roadway projects. The analysis includes investigating the interchange to determine if the projected traffic demands can be met by the proposed design.

In conjunction with the Congestion Management Section, the Section is involved in the planning and implementation of incident management plans for major urban areas in the State. This includes the identification of alternate routes for major arterials, and traffic operation plans for the alternate routes, including the development of closed-loop signal system and system timing plans.

The Section investigates and evaluates new technology developed for use at signalized intersections. The Section develops and designs pilot programs using the new technology. Evaluations generally include not only direct benefits to traffic operations, but also indirect benefits to the environment through decreased pollution and energy consumption. Some examples of the new technology include Light Emitting Diode (LED) traffic signal lights, fiber-optic signage, SCATS and SCOOTS timing systems, and improved vehicle detection schemes. Traditionally, vehicle detection methods utilize a wire embedded in the roadway to detect vehicles. The Section is involved in researching and developing "out-of-Pavement" vehicle detection methods. Some of these methods include video imaging detection, infrared detection, microwave detection, and ultrasonic detection.