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C H A P T E R 2 Background, Hypothesis, and Methodology This chapter highlights the significance of NRC and the level of potential. Minimizing the causes of NRC involves reducing the conventional strategy applications deployed to date. It identifies incidence or the causes of unreliability through either pre-event the business process needs of effective SO&M and develops a actions (e.g., speed control, advisories, deicer application) hypothesis about the relationship with institutional architecture. or postevent minimization of the impact of the incidence (e.g., rapid crash clearance, rapid snow removal). The strategy Focus on NRC applications themselves combine the following: Over the last decade, new metropolitan highway capacity ITS applications--typically a control device and communi- increases have averaged less than 2% per year, outpaced by cations infrastructure or software-based platforms (capital growth in vehicle miles traveled (VMT). Highway level-of- projects that need to be engineered); service (LOS) continues to deteriorate in major metropolitan Related procedures and protocols (that need to be devel- areas in most states, as growing demand exceeds available oped and documented)--actions are taken in real time by capacity. These capacity shortfalls result in increasing, recur- participants in conjunction with the ITS applications; and ring (peak) congestion. Given current budgets, as well as Development of concepts of operations as a tool to identify environmental and energy constraints, there is little likelihood roles, infrastructure, and information transfer (requiring that new capacity will be made available at the network level agreement among participants), upon which the procedures to substantially relieve this type of congestion. and protocols are based. At the same time, NRC related to crashes, bad weather, high- way construction/maintenance, and special events produce The strategy applications that have been developed for NRC additional delays and disruptions that are largely independent of are typically centered within the larger highway jurisdictions-- the capacity situation. Table 2.1 presents the causes of conges- state DOTs, toll entities, and the large local government tion by level of urbanization. NRC is responsible for more than transportation agencies--together with their public safety half of the total delay and most of the lack of reliability experi- partners. Although the focus is often on expressways, the enced on the U.S. highway system. The negative impact of NRC applications are also used for major arterials and rural routes. on highway operations is even more pronounced in smaller These conventional strategy applications include the following: urban and rural areas. This unpredictability is of special concern in a society that values reliability and just-in-time service. Incident management, including multijurisdictional inte- NRC also heightens crash potential. Every minute of lane grated corridor management in response to crashes, break- blockage from crashes, breakdowns, or weather can translate downs, hazardous materials spills, and other emergencies; into 3 to 7 min of flow recovery after the lanes are cleared. Road weather management in response to heavy rain and Secondary crash likelihood increases by 2 to 3% for each wind, snow, and ice; minute of queue continuation. Work zone traffic management focused on traffic control plans to minimize the impacts of reduced capacity; Special events planning and management to accommodate Effective Strategy Applications event patrons with minimum traffic disruption; and to Reduce NRC Active traffic management using lane use and speed con- Specific effective strategy applications to reduce the impacts trol to minimize flow disruption and incidents, as well as of NRC are known but are nowhere near being used to their managing diversions and the operation of diversion routes. 18