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HomeMy WebLinkAboutIR 10010 INFORMAL REPORT TO CITY COUNCIL MEMBERS No. 10010 To the Mayor and Members of the City Council May 9, 2017 DJA� Page 1 of 2 SUBJECT: OPERATION OF TRAFFIC SIGNALS AND STREET LIGHTS 1675 The purpose of this informal report is to provide information on the operation of traffic signals relative to their timing and synchronization and the operation of street light fixtures and how they are programmed to turn on and off. Street Light Operations The City maintains over 66,000 street lights located along City streets and freeway facilities. The street light fixtures are programmed to turn on and off through use of a photocell that is wired to control an individual fixture or a series of fixtures, depending upon the physical layout of the lighting and its connection to the electric power source. The photocell measures the amount of ambient light in the area and when it decreases to a certain level, controls a power switch in the street light fixture electrical system that allows current to flow to the fixture. The reverse occurs when the ambient light increases and the photocell turns the power switch to the off position, stopping the flow of electrical power. The City's street lights are not controlled by a central system. Throughout the year, the on and off time periods of the street light fixtures adjust with daylight savings time changes. If street light fixtures are lighting during the day or not activating at night, the photocell is likely not operating correctly, which requires staff to physically address the malfunction. In the future as technology advances and becomes cost effect, smart street light fixtures will be able to communicate wirelessly with a central system to indicate power outages or inoperative components. Traffic Signal Operations The city currently operates and maintains 875 signalized intersections that are controlled by 762 traffic signal controllers. 113 signalized intersections share operations with a single traffic signal controller. This condition occurs most frequently at freeway intersections with frontage roads in both directions and other closely space intersections where coordinated operations are required to optimize capacity. In these situations, depending upon the location, one traffic signal controller may manage signal timing at two, three or four intersections. The retiming of traffic signals is scheduled to occur once every three years. Approximately 300 intersections are retimed each year to improve operations in response to changes in travel patterns. Some locations are retimed more frequently in response to localized changes in development, new travel patterns, new roadway segments, and changes in pedestrian and bicycle utilization. The continued growth and redevelopment throughout the City, creates ongoing changes in vehicle, pedestrian, and bicycle travel patterns and the need for improved traffic signal timing. Synchronization or coordination of traffic signals exists along many major thoroughfares throughout the City as well as in the downtown area. There are 639 intersections that operate in a coordinated manner, 140 in the downtown area and 499 intersections along 40 major thoroughfares. In FY 2016, 20 major thoroughfares were retimed in a coordinated manner, which included 240 intersections. In FY 2017, 35 corridors, 300 intersections, are scheduled for retiming. ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS INFORMAL REPORT TO CITY COUNCIL MEMBERS No. 10010 To the Mayor and Members of the City Council May 9, 2017 DJA� Page 2 of 2 SUBJECT: OPERATION OF TRAFFIC SIGNALS AND STREET LIGHTS 1675 Effective coordination of traffic signals is achieved when communication exists across intersections such that the clocks for each signal controller are synchronized. If the clock for a traffic signal drifts over time, the sequencing of light changes will not occur as designed, resulting in vehicles stopping or slowing down as they approach the next intersection. Today, communication exists at 300 intersections - downtown intersections and along several major corridors. This communication system is a combination of wire (copper and fiber optic) between signals and wireless cellular modems. As part of the 2014 Bond Program, the communication system is being improved and expanded so that all signal controllers will have communication capabilities. Copper wire connections are being replaced with wireless cellular modems to improve reliability, especially during wet weather conditions. Through this effort, traffic signal timing will be more reliable and failures of equipment will be automatically reported so that maintenance actions can be performed remotely via the communication system or a technician may be quickly dispatched. These communication improvements are scheduled to be completed by December 2018. In addition to communication improvements, recent programming of PayGo funds has provided funding to allow major maintenance of outdated electrical components. Maintenance of these improvements are critical for effective operations to be maintained to minimize the occurrence of the traffic signal going into Red Flash operations. This Red Flash operation usually occurs when electrical equipment fails as a result of electrical power surges, lighting strikes/system power surges, or moisture coming in contract with old wire. The last two years of additional PayGo maintenance has resulted in a decrease in the number of occurrences of Red Flash operations from 131 per month in FY 2016 to 56 per month so far in FY 2017. If you should have questions, please contact Douglas Wiersig, TPW Director, at 817-392-7801. David Cooke City Manager ISSUED BY THE CITY MANAGER FORT WORTH, TEXAS