Performance Measurement for Highway Winter Maintenance Operations, TR-491, 2009

(2009) Performance Measurement for Highway Winter Maintenance Operations, TR-491, 2009. Transportation, Department of


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TR-491 Tech Brief.pdf

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The goal of this research project was to develop a method to measure the performance of a winter maintenance program with respect to the task of providing safety and mobility to the travelling public. Developing these measures required a number of steps, each of which was accomplished. First, the impact of winter weather on safety (crash rates) and mobility (average vehicle speeds were measured by a combination of literature reviews and analysis of Iowa Department of Transportation traffic and Road Weather Information System data. Second, because not all winter storms are the same in their effects on safety and mobility, a method had to be developed to determine how much the various factors that describe a winter storm actually change safety and mobility. As part of this effort a storm severity index was developed, which ranks each winter storm on a scale between 0 (a very benign storm) and 1 (the worst imaginable storm). Additionally a number of methods of modeling the relationships between weather, winter maintenance actions and road surface conditions were developed and tested. The end result of this study was a performance measure based on average vehicle speed. For a given class of road, a maximum expected average speed reduction has been identified. For a given storm, this maximum expected average speed reduction is modified by the storm severity index to give a target average speed reduction. Thus, if for a given road the maximum expected average speed reduction is 20 mph, and the storm severity for a particular storm is 0.6, then the target average speed reduction for that road in that storm is 0.6 x 20 mph or 12 mph. If the average speed on that road during and after the storm is only 12 mph or less than the average speed on that road in good weather conditions, then the winter maintenance performance goal has been met.

Item Type: Departmental Report
Keywords: Average travel speed, Crash rates, Highway safety, Mobility, Performance measurement, Winter maintenance
Subjects: Transportation
Transportation > Roads and highways
Transportation > Environment
Transportation > Environment > Weather and climate
Transportation > Maintenance and preservation
ID Code: 20049
Deposited By: Iowa DOT Library
Deposited On: 07 Jul 2015 12:24
Last Modified: 22 Jan 2018 14:07