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Congestion Management Process

Federal law requires that metropolitan regions with more than 200,000 people (known as Transportation Management Areas [TMAs]) maintain a Congestion Management Process (CMP) and use it to improve transportation planning and decision making. Current surface transportation law intends the CMP as an integrated process that augments the overall metropolitan planning process. The goal is a systematic, transparent way for transportation planning agencies to identify and manage congestion, and utilize performance measures to direct funding toward projects and strategies that are most effective for addressing congestion. While the Rockingham MPO is not technically a TMA, a significant portion of the region is located within the Boston Urbanized Area and so a CMP was developed in 2010 based around the major transportation corridors.

System Definition

There is a backbone of transportation routes that carry the majority of long distance travel within the region as well as to and from adjacent regions. These routes carry the highest volumes of people and goods between the communities and the regional employment and other activity centers. These routes tend to be on the National Highway System (NHS) and are made up of Interstate Highways, Expressways, and other Principal Arterials. These roadways in the RPC are:

  • Interstate 95 (I-95) is an eight lane, toll facility that crosses the southeastern portion of the RPC between Massachusetts and Maine.
  • Interstate 93 (I-93), a grade-separated freeway, is located in the western part of the region and runs north/south from Massachusetts through Salem and Windham and north to Manchester, Concord, and northern New Hampshire.
  • NH 101 is the region’s major east-west highway and in the past was a high traffic and high accident corridor.
  • NH 16, also known as the Spaulding Turnpike, is a north-south, limited access toll roadway which carries commuter and tourist traffic, and serves as a gateway from the Seacoast to the Lakes Region.
  • NH 125 is primarily a 2 lane roadway that carries traffic from Massachusetts through Plaistow, Kingston, Brentwood and Epping where it exits the RPC region.
  • Interstate 495, although outside of the RPC region, is an important facility which follows an east-west path through the center of the adjacent Merrimack Valley Region.
  • US 1 is a heavily developed two lane roadway for most of its length that provides local connections to communities along the seacoast, access to NH beaches for tourists, as well as high levels of commercial activity.
  • US 1 Bypass: The US 1 Bypass connects US 1 from the south end of Portsmouth to I-95 and the Spaulding Turnpike (NH 16) and then continues across the Sarah Long Bridge to Kittery, ME.
  • NH 28 provides a parallel route to Interstate 93 in Salem and Windham and on to Manchester.
  • NH 33 provides a connection between Stratham where it intersects with NH 108 at the Stratham circle and I-95 in Portsmouth where it serves as a western route around the Great Bay.
  • NH 107: NH 107 connects US1 and Interstate 95 in Seabrook with NH 150, NH 108, and NH 125 to the west before turning northward and crossing NH 101 outside of the RPC region at Exit 5 in Raymond.
  • NH 108 is a two lane roadway with ADTs ranging from 5,000 vehicles per day at the Massachusetts border in Plaistow, to 23,000 per day in Exeter and Stratham, where it serves commuters, commercial traffic, and provides a connection to NH 101.
  • NH 111 provides a second east-west route through the RPC region that connects the coast in North Hampton to Windham, and continues west to Nashua.
  • COAST, The Cooperative Alliance for Seacoast Transportation provides bus transit service in Exeter, Stratham, Greenland, Portsmouth and Newington, with connections northward to Dover, Somersworth, Rochester, Farmington, and South Berwick, Maine.
  • Intercity bus service is available in the I95, I93, and NH Route 125 corridors, with an emphasis on Boston-bound commuter travel as well as access to Logan Airport
  • Amtrak’s Downeaster service between Portland and Boston includes several station stops in Southern Maine, Northern Massachusetts, and three New Hampshire communities – Exeter, Durham, and Dover.
  • The eight Park & Ride facilities in the region operated by the NH Department of Transportation (NHDOT).


Congestion Management ProcessThe full Congestion Management Document provides additional detail regarding the system as well as defining the performance measures that will be utilized. In addition, the document establishes a performance monitoring plan and provides details regarding how the CMP will be implemented.