Arizona State and Local Government Documents Collection

Project Summary

Passing and climbing lanes provide additional lanes for vehicles to safely pass other vehicles while maintaining speeds. Implementing passing and climbing lane projects provides traffic operational and safety benefits at a cost that is far less than fully widening a highway. In an effort to enhance safety and mobility on Arizona's roadways, the Arizona Department of Transportation is currently updating the 2003 Passing and Climbing Lanes Prioritization Study. This update intends to further refine the identification and prioritization methodology previously utilized and to develop a prioritized list of candidate locations that would provide the most benefit to the traveling public.
Study Objectives

    Review previous studies and research current best practices.
    Analyze the safety and performance benefits of passing/climbing lanes constructed since the previous study.
    Develop a revised methodology and ranking criteria.
    Obtain feedback from ADOT District Engineers and other stakeholders, such as rural COGs and MPOs.
    Develop a new prioritized list of candidate passing/climbing lane projects. 
 

Composite materials using asphalts, mineral dusts, and a class of chemical coupling agents known as reactive silanes are prepared for use as binders in paving construction where asphalt alone is in general use at the present. The report describes how these coupling agents may, in very low concentrations, react with both asphalts and mineral dust fillers at the interfaces of their mixtures to integrate them into new materials which may appropriately be termed composite materials. Differing asphalts, mineral fillers, and silanes are considered. Also, wide ranges in composition and differing manufacturing methods are described. The report leads through a series of phases in development and characterization of composite products and in the evolution of the concepts and criteria felt by the author to be required for manufacture and control of superior composite binders.

This research study of pavement smoothness measurement was conducted in order to develop and implement an improved highway smoothness construction specification on asphalt concrete pavements. Achieving a higher level of smoothness on highways during construction results in savings to the taxpayer due to reduced wear and tear on vehicles, and longer highway life. Although the current ADOT specification used for highway smoothness addresses localized smoothness problems, it is difficult to administer due to the measurement system used, and provides little impetus to the contractor to improve his quality of work with respect to overall highway smoothness. This study provided data to assist ADOT in developing a new smoothness specification that would provide incentive to contractors to construct smoother pavements and which is easier for ADOT to administer. In order to provide incentive to contractors, a pavement smoothness construction quality control draft specification and associated measurement procedure was produced.

The effects of increased truck loads and higher tire pressures on performance of flexible pavements were investigated in this project. This Volume 1 report presents the research performed and the useful results obtained. Tire pressure studies were performed using both in field measurements and theoretical simulations of the effects of tire pressures on pavements. Volume 2, provides documentation for all of the computer programs developed on the project.