Optimizing signal timing is considered a low-cost approach to reducing congestion. Based on data from six separate studies, the costs range from $2,500 to $3,100 per signal per update. While this range is reasonable, costs could be slightly more or less. A cost summary from the Metropolitan Transportation Commission (MTC) study is presented below; links to cost summaries from the other five studies as well as the synthesized costs summary are also provided.

The Metropolitan Transportation Commission (MTC) is the transportation planning, coordinating and financing agency for the nine-county San Francisco Bay Area. The MTC’s work is guided by a 19-member policy board. A link to the MTC Arterial Operations website can be found at http://www.mtc.ca.gov/services/arterial_operations/current.htm.

The MTC’s 2001 Regional Transportation Plan (RTP) provided $1.2 million per year in regional funds for traffic signal coordination to improve mobility and air quality. The $1.2 million are federal funds with MTC providing the local matching funds. As a result of the RTP, the Regional Signal Timing Program (RSTP) was formed beginning in 2003/2004. Through the RSTP, MTC retains consultants to assist in developing and implementing new time-of-day signal coordination plans for weekday peak periods. There are approximately 7,000 signals in the San Francisco Bay Area of which approximately one-half operate as part of a coordinated system. The RSTP calls for the retiming of the coordinated signals at least once every five years. MTC plans for the retiming of about 700 signals per year.

The results of the 2005 Cycle were published in a memorandum to the MTC’s Operation Committee. According to the memorandum, a total of 11 of the 16 approved projects were completed resulting in the retiming of 449 signals. The total cost of the completed projects was $1,076,380. Using this data yields an average cost of $2,400 per signalized intersection. Additional analysis yielded a benefit cost ratio of 39:1.

The MTC established guidelines (http://www.mtc.ca.gov/services/arterial_operations/downloads/RSTP/RSTP_Guidelines.doc) for the RSTP. The fee schedule used by MTC to pay consultants for technical assistance for retiming signals is provided in the guidelines. The fees are lower that the average cost experienced by the 2005 program cycle for two reasons:

1) The fee does not reflect local agency staff costs for reviewing all of the consultant’s deliverables, or if selected, to implement the timing plan themselves. For benefit cost calculations, MTC marks up the fee paid to the consultant by 25% to account for local agency costs.

2) The fee does not reflect additional services that may be requested by the local agency that go beyond the standard scope of work. Examples of additional services include, but are not limited to transit signal priority, additional field work when the consultants find that the existing timing sheets provided by the local agencies are not current, additional fine-tuning, additional fee associated with projects that involve very few signals (in which case the assumed economies of scale do not apply).

In each case, MTC includes in the total cost the actual fee paid to the consultant per project.

Related links:

Synthesized Costs of Traffic Signal Retiming
Cost range for retiming traffic signals: $2,500 to $3,100 per signal per update.

National Traffic Signal Report Card
Costs to update signal timing: $3,000 or less per intersection.

Millenia Mall Signal Retiming Project
Cost of retiming signals: $3,100 per intersection.

Benefits of Retiming Traffic Signals: A Reference for Practitioners and Decision Makers About the Benefits of Traffic Signal Retiming
Cost range for signal retiming: $2,000 - $2,500 per intersection.

The Benefits of Retiming Traffic Signals
Costs of retiming traffic signals is roughly $2,500 per intersection.
Costs of retiming traffic signals in the Washington, DC area is about $3,500 per intersection.

Denver Regional Council of Governments Costs of Retiming Traffic Signals
Cost to retime each signal ranges from $1,800 to $2,000 which includes consultant time and DRCOG staff review time.