美国养护工区特征分析

coding rubric, all lane closure schedules are reported as the latter –as periods when traveler is certain to encounter a lane closure.

Although the state web resources provided the best breadth of coverage of work zone activity of the three web sources considered, they cannot report every work zone

statewide--there are simply too many. Unsurprisingly, the state websites report primarily on the facilities that reflect state responsibilities: interstate, US highway and state routes. No more than 11% of the work zone records examined dealt with roadwork on local streets in any of our snapshot analyses.Clearly, additional roadwork also occurs within the boundaries of the states considered here. Therefore, the data collected in this study from state websites should not be construed as a completely representative illustration of all maintenance, construction and utility activity across the nation, but rather as a subsetfocusing on major facilities where road construction and maintenance activities are primarily state responsibilities.

From the 2001 pilot study to our more recent snapshot analyses, several clear trends have emerged in the format and content of state roadwork websites:

the pilot study, there were 15-20 states to choose from when selecting a sample for

analysis. By 2002, the number of potentially useful state websites had roughly doubled. At this point (2004), all stateshave websites reporting work zone information of some kind.and appeared to primarily target contractors and other involved directly in the roadway projects. In 2003, 25-50% of state websites have moved to a road-user perspective reporting daily lane closures.posting work zone data. For example, in the 2002 summer season, Maine reported data on two major projects. After a website redesign effort in the summer of 2002, Maine reported data on over 200 work zones.

THE NATIONAL WORK ZONE PICTURE

In this section, an overview of findings from all of the five snapshot studies is presented to provide a broad national characterization of work zone activity. First, an analysis of primary data elements is presented, such as project duration and lane closure schedules(Table 2). Second, from these basic elements, national-level measures are derived, including the total number of work zones on the National Highway System (NHS), the percentage of the NHS with work zones, and an estimate of capacity loss from work zones. The NHS is a designated collection of 163,000 miles of roadway critical to the nation’s economy, defense, and mobility. The NHS is composed of interstate highways