TRAFFIC OPERATIONS LABORATORY RESEARCH

Evaluation of Speed Photo Enforcement in Illinois Work Zones
Work zone safety and efficiency of operation is important to road users and roadway authority. The Illinois Department of Transportation (IDOT) is interested in evaluating the effects of using speed photo enforcement (SPE) systems on traffic flow characteristics and safety in work zones (WZ). A vendor will provide the equipped vans to IDOT and will train the Illinois State Police (ISP) and IDOT personnel on how to use the system. The overall goal of this study is to determine the effectiveness of SPE in work zones. Data will be collected on speed, speed variation, speeding tickets issued, and fraction upheld as valid in courts.

Evaluation of Uninterruptible Power Supply (UPS) Systems at Signalized Intersections
Uninterruptible Power Supply (UPS) systems are being used at critical signalized intersections to power traffic signals in the event of a power failure. The performance characteristics and runtime of UPS systems from four manufacturers were evaluated. The runtime and operation of certain features of the systems were compared to IDOT interim specification. The findings were used in finalizing the IDOT specifications for UPS systems. All four systems were found to satisfy majority of the specifications.

Effects of Temperature on Performance of Uninterruptible Power Supply Systems
Uninterruptible Power Supply (UPS) systems installed at the traffic signals are subject to the wide range of weather conditions. Consequently they were evaluated at the extreme hot and cold temperatures that are experienced in Illinois. This study evaluated the performance of four different systems at hot and cold temperatures. Effects of temperature on runtime of the systems were determined. The finding provided very valuable insights into the performance of the UPS systems and how to increase the utility of these systems in adverse weather conditions.

Turn-on and Turn-off Characteristics of Traffic Signal LED Modules
Incandescent traffic signals modules are being replaced with more energy-efficient Light Emitting Diode (LED) modules at various intersections. LED lights use 10-15% of the energy used by the incandescent lights. LED modules from different manufacturers do not seem to turn on and turn off at the same time and may confuse some drivers. This study examined and quantified the phenomenon.

GIS-based integrated Intersection Inventory System
Information about intersections resides in different data bases and is not easily accessible. This study developed a GIS-based Intersection Inventory System (GIS-IIS) for the signalized intersections on the state-maintained highway system. Procedures were developed for field data collection and processing as well as integrating multimedia and other traffic signal information into the GIS framework. It was recommended to expand GIS-IIS to create a comprehensive information system that incorporates information such as traffic, geometric, construction, maintenance, and intersection accident data.