Source: Travelmidwest.com

One of the most widespread and invisible pieces of intelligent transportation system (ITS) equipment is the vehicle detector, which is used to collect information about road traffic conditions. According to the Research and Innovative Technology Administration (RITA) 2010 ITS Deployment Survey, there are approximately 3,500 loop, video, and radar traffic detectors installed on arterials in northeastern Illinois. There are an additional 1,300 loop, radar and toll tag detector stations on the region’s expressways and tollways. This critical component of the region’s ITS system is easily overlooked, but the system operators have invested millions of dollars to deploy them on our expressways, tollways, ramps, and arterials. Detectors improve traffic signal operations and our ability to monitor and manage the system. Eight-four percent of our region’s freeway miles and 46 percent of the region’s signalized intersections are currently covered by electronic surveillance.

Vehicle detectors collect information about the presence or number of vehicles as well as vehicle speeds, multiple times per minute around the clock. However, vehicle detectors are only useful when they communicate the information they collect to places where it can be put to use, such as to traffic signal controller boxes to trigger green signals, to agencies where they can monitor traffic conditions and detect incidents, and to the public where information about traffic conditions can be used to make informed travel decisions. Accordingly, the thousands of vehicle detectors are accompanied by a vast communications infrastructure made up of copper wires, fiber optic cables, and wireless communications. As the region’s transportation network communication infrastructure is expanded, and backroom computer technology for interpreting the information evolves, we will improve our ability to manage the system in real time and even predict traffic congestion before it happens. In addition, in-vehicle data is now being collected for some cars and trucks; this data is providing an increasingly valuable data source for system traffic managers and will be the subject of a future post.

The Illinois Department of Transportation (IDOT) is undertaking projects and programs to improve its detector system. First, I-55 and I-80 detection is now being expanded to include most of those expressways within our region. Second, over the next several years, expressway system surveillance will be expanded to include the entire Chicago metropolitan region. Third, IDOT regularly checks arterial and expressway detectors and repairs them as necessary and as traffic conditions allow.

As a resident of northeastern Illinois, vehicle detection impacts your daily travel if you plan your trip using Travelmidwest.com or Lake County Passage, which receive vehicle detector information in real time; at a traffic signal, where a detector informs the signal that you are waiting to proceed; when you read message signs providing travel time information; when you enter the expressway at one of the 113 metered ramps; if you wonder about the schedule for the Kennedy reversible lanes; when you drive through an open road toll location; or when you see a sign warning of a traffic backup ahead.