Wilson Street Traffic Signal Interconnect
Project Description & Locations
This project involves traffic signal interconnect, traffic signal modernization, emergency pre-emption system and pedestrian signals at the following intersections:
Since the signal system will be interconnected with the signals on the Illinois Department of Transportation (IDOT) roadways, the majority of this project will be funded by IDOT.
For the design of this project the City has contracted with Civiltech Engineering Inc. to perform all necessary tasks including surveying, design and plan preparation. Civiltech is currently working on the proposed design plans for the remaining three intersections to be constructed in 2013 & 2015.
In Fall 2012, the first two intersections as noted above will begin construction and be completed in April of 2013. For more information regarding this construction click here.
Traffic Signal Interconnect
The goal of a traffic signal interconnect is to synchronize and coordinate the intersections in a specific corridor allowing for platoons of traffic to travel more smoothly and quickly with maximum green-light time, through the corridor. Essentially getting the greatest number of vehicles through the system with the fewest stops and/or travel time. It would be ideal if every vehicle entering the system could proceed through the system without stopping. This is not possible, even in well-spaced, well designed systems. Therefore, in traffic signal interconnect systems, the majority rules and the busiest traffic movements are given precedence over the smaller traffic movements. This means that side street traffic will typically experience a longer wait time. However, once on the major roadway, motorists should generally experience better free flowing traffic conditions. An associated benefit of traffic signal coordination is a reduction in pollution. Improved traffic flow reduces vehicular emissions through reduced idle time and more efficient operation. How well traffic flows along a street depends on several factors:
the spacing between traffic signals along the street
programmed signal timing parameters
number of traffic lanes and their availability
driver behavior and driving speed
physical characteristics of the roadway
frequency of left turn arrows
roadway width (wider roadways increase pedestrian walk/don' walk timing)
amount of pedestrian activity
Traffic Signal Modernization
Traffic signal modernization involves updating and in some cases relocating the locations of the existing equipment. The purpose of traffic control devices (signs, signals, and pavement markings) is to help provide safe, orderly, and predictable movement of traffic. Improper or overuse of devices may reduce safety and efficiency of traffic flow. State and national standards and uniform state vehicle codes have been developed to provide uniformity of appearance and proper application of devices. For example, imagine the confusion of drivers if each city or county used traffic signals with a different color, shape, and meaning.
Emergency Pre-Emption SystemEmergency Pre-Emption systems will be in place at all of the intersections in this project to be used by authorized emergency vehicles, including fire engines, ambulances and police vehicles.. When activated by the flashing lights on an authorized emergency vehicle, it transfers control of the traffic signal over to a special priority signal operation which allows the emergency vehicle to proceed through the area easier. When the Emergency Pre-Emption System is activated it will instruct the signals to change to a specific green like sequence to favor an approaching emergency vehicle. When an emergency vehicle pre-empts the normal operation of the signal, the signal is thrown out of coordination with the rest of the signal system. It can take several cycles before an individual traffic signal can "catch up" and return to coordination with the rest of the system.
These will be installed at all of proposed intersections to aide in safe crossings for both walking and biking pedestrians. There are several different types of pedestrian signals and systems what are being evaluated. The City is particularly looking into using Countdown Pedestrian Signals. These signals show the same information as the conventional pedestrian signals, but with the addition of a countdown timer that shows pedestrians how much time they have to complete their crossing.
For questions regarding this project, contact:
Noel Basquin, City Engineer at firstname.lastname@example.org or 630-454-2760 or
Karen Young, Assistant City Engineer at email@example.com or 630-454-2756