Introduction to Transportation Demand Management Traffic congestion affects just about everyone who drives in New Jersey. Whether it's the delays we experience on our morning commute, traffic jams on the way to the beach, backups at the mall, rubberneck responses to accidents, or slowly getting through those ubiquitous construction zones, the result is the same - wasted time and wasted fuel. According to the Texas Transportation Institute, the average New Jerseyan spends 45 hours a year stuck in traffic. And it doesn't look like it's going to get any better - the New Jersey Department of Transportation's 2001 Long Range Transportation Plan Update states that traffic congestion is the biggest transportation problem facing New Jersey in the next 25 years. So, what causes all this traffic? It's pretty simple. Congestion occurs when demand (the number of vehicles on a road) exceeds the supply (the carrying capacity of the road). Accordingly, traffic congestion can be addressed by both supply side and demand side strategies. Supply side strategies include building new highways and widening existing highways to increase the carrying capacity of the transportation system. While these kinds of strategies can be effective in reducing travel times in the short term, in the long term they induce additional development and traffic and the problem keeps getting worse. Demand side solutions, or Transportation Demand Management (TDM), seek to maximize the efficiency of the transportation system by managing demand, rather than by increasing supply. They are designed to get more out of existing transportation resources and can be an effective tool to mitigate the traffic impacts of development. Demand management strategies fall into four broad categories: Increasing the number of persons in a vehicle (see TDM Strategies to Increase Vehicle Occupancy) Influencing the time or route of travel (see TDM Strategies to Influence Travel Time or Route) Facilitating shifts from automobile to transit or non motorized modes (see TDM Strategies to Facilitate Mode Shift TDM Strategies to Eliminate Trips) Eliminating the need for travel (see TDM Strategies to Facilitate Mode Shift TDM Strategies to Eliminate Trips) For years, solutions to traffic congestion were dominated by supply side strategies that catered to the automobile. Beginning in the 1950's and continuing through the 1980's, massive highway projects changed the landscape of New Jersey. Toll roads and interstate highways were constructed, state highways were widened and converted into limited access facilities and county roads were expanded to link into the new highways. This paved the way for ex-urban and rural development and its resultant dispersion of jobs and housing. In 1950, only 7% of the US land area was classified as urban; that number increased to 20% by 1995. At a regional level, land use consumption skyrocketed as well. According to figures from the Delaware Valley Regional Planning Commission, land was gobbled up for development at an astonishing rate of an acre per hour in the Delaware Valley between 1977 and 1990, resulting in more vehicle trips per person, more vehicle miles traveled and steadily diminishing investment in cities and public transit. As population and jobs spread out, driving patterns changed. As a result, additional supply side projects such as beltways, bypasses and widening existing routes that once only served local traffic, became commonplace. Instead of building our way out of congestion, we built our way into it. The Federal Highway Administration's Office of Operations reports that almost 15% of the nation's 42,500 miles of congested roadways were in rural areas in the year 2000. In addition to the social costs, road building is expensive. According to the Federal Highway Administration the average cost of constructing a mile of new federal aid highway between 1990 and 1994 was $2.8 million, not including right-of-way acquisition. These high financial costs, together with concerns about environmental impacts, historic preservation and protecting communities, have caused government officials to re-evaluate highway expansion projects. Instead, they are looking at how to better manage the existing transportation system. Many are finding that carefully planned demand side strategies such as Transportation Demand Management, which optimize the "people moving" capacity of the transportation system without creating more physical infrastructure, can contribute to a more efficient and accessible transportation system.