Sources of Congestion Poor Signal Timing 5%
Special Events/Other 5%
Bad Weather 15%
Bottlenecks 40%
Work Zones 10%
Traffic Incidents 25%
Figure 31: The Sources of Congestion National Summary - FHWA (https://ops.fhwa.dot.gov/aboutus/opstory.htm) Historically, the Pennsylvania Department of Transportation (PennDOT) has utilized the Work Zone Delay Analysis Workbook to analyze work zone impacts. Recently, the Safety and Traffic Operations in partnership with the Bureau of Maintenance and Operations (BOMO) of PennDOT have decided to use a freeway evaluation software FREEVAL (FREeway EVALuation) to determine highway efficiency under work zone conditions. The FREEVAL, which is based on analytical formulas of the 6th edition of the Highway Capability Manual, is a tool for freeway analysis that could be calibrated and used to assess the possible scenarios of work zone activities in those areas. However, not all work zones are located on the freeways or rural and suburban highways. Therefore, to assist in developing practical plans to evaluate and manage the anticipated type, severity, and extent of work zone impacts on travel time and delay, there is a need to identify appropriate analytical tools and methods for different types of work zones in other (e.g., urban) areas.
7.1 Work Zone Analysis Tools Federal agencies paid considerable attention to improving the safety and mobility of work zones, mostly after 1991, when the Intermodal Surface Transportation Efficiency Act (ISTEA) mandated a highway work zone safety program to enhance the safety at highway construction sites. Afterward, multiple legislation, regulations, and initiatives in the past two decades have been declared and adopted. These initiatives aimed at enhancing safety, facilitating the management of the mobility impacts of work zones, implementing a policy for the systematic 61
