Arizona State and Local Government Documents Collection

As part of the Long Term Pavement Performance (LTPP) Program, the Arizona Department of Transportation constructed 19 Specific Pavement Studies 6 (SPS‐6) test sections on Interstate 40 near Flagstaff. The SPS‐6 project studied the effect of specific rehabilitation treatments on jointed portland cement concrete pavement (JPCP) performance. The test sections had various JPCP surface preparations, including crack and seat, minimum and maximum restoration, rubblization, asphalt concrete (AC) with fabric, and asphalt rubber with conventional AC. Opened to traffic in 1991, the project was monitored at regular intervals until 2002. Surface distress, profile, and deflection data collected throughout the life of the pavement were used to evaluate the performance of various flexible pavement design features, layer configurations, and thickness. This report documents the analyses conducted as well as practical findings and lessons learned that will be of interest to ADOT.

A comprehensive research program for the characterization of storm water runoff from an Arizona highway was conducted from January through December 2007. The study area covered a portion of the Loop 202 freeway west of Mesa Drive to a retention basin east of Lindsay Road in Mesa, Arizona. Storm water samples were collected from two storm water detention basins and a discharge point to the Salt River. The study was conducted by manually collecting storm water samples with passive automatic samplers and analyzing them for various roadway constituents. A primary objective of this research effort was to establish baseline values of constituents in ADOT highway runoff, aiding in the evaluation of related best management practices. A total of 16 storm water samples was collected from the research area between January 2007 and December 2007.

This project required the completion of Construction Data Forms for the Strategic Highway Research Program's (SHRP's) Specific Pavement Studies (SPS) Experiment Number 5, The Rehabilitation of Asphalt Concrete Pavements, and Experiment Number 6, The Rehabilitation of Jointed Portland Cement Concrete Pavements. In Arizona, the SPS-5 experiment construction was done in the eastbound travel lane of Interstate Highway 8, between mileposts 159 and 161 in southwestern Arizona. Eleven test sections were constructed for the experiment, with eight as set forth in SHRP guidelines. In addition, two additional sections were constructed, and one designated as the control section, for a grand total of eleven sections.

Under contract HFR-PL-1(31)264, "Concrete Pavement Design and Rehabilitation," a comprehensive data base was created which contains pavement design and construction data, climatic information, traffic data, and condition data for 48 pavement sections. The data base includes projects from jointed concrete pavements (40 sections), prestressed concrete pavements (4 sections), continuousIy reinforced concrete pavements (2 sections), and 3-layer structural rehabilitation pavements (2 sections).

This project was undertaken to compare operational and safety characteristics of leading versus lagging protected left turn operation. The measures of effectiveness included field measured intersection delay with leading and with lagging left turns. Intersections in Pima County, Glendale, Tempe and Mesa, Arizona were studied with both leading and lagging operation. Intersection delay studies were also done with first car versus third car actuation of leading protected left turn phases. Signal progression was studied with leading, lagging and combination of leading and lagging left turns which provided the best progression. This evaluation was accomplished with an instrumented vehicle and travel time runs throughout a grid. Accident studies were conducted in Tucson, Pima County and Scottsdale, Arizona. These studies compared accident frequency before and after the conversion from leading to lagging left turns. A public opinion survey was conducted to obtain motorists' preference of leading or lagging left turns.

Guidelines were developed to assist the Arizona Department of Transportation (ADOT) in (1) determining if an existing sign installation, not in compliance with current safety standards, should be replaced by a system that does meet the safety standards, and (2) selecting a cost effective sign support for new installations. A benefit/cost (B/C) program, developed at the Texas Transportation Institute (TTI) was used to develop the guidelines.