Transportation Demand Management: What is it and why do you want it?

As the economy starts to show some signs of a turnaround, there seems to be a buzz about projects that may start and how to proceed with them. In New York City, as well as around the country, many of the larger projects might look quite different from a traffic engineering standpoint than they did two or three years ago. During those few years, a series of factors caused reduced funding while the country continued to move more into green and sustainable development. If you're one of the developers, owners or operators involved in a large scale project, these changes may cause you to think about Transportation Demand Management (TDM). TDM refers to a series of measures implemented to more evenly distribute user/patron trips to a site across a variety of transportation modes. The goal of this redistribution is to reduce overall vehicle trips by minimizing single occupant vehicles. TDM Benefits Vehicle reduction can mean less cost mitigating the impacts of increased traffic. For large scale developments, these costs can rise to the seven figure level with new signals, intersection modification and other capital costs. Also, if fewer vehicles are coming to a particular site, less parking can be provided (if permitted by local zoning requirements). Less parking, especially in high density urban environments, can mean less excavation, structure and overall construction cost. It also allows additional space for the development program (i.e. building or green space) in lieu of parking. TDM is a sustainable or "green" approach. Reducing vehicle volumes and increasing other modes of transportation such as mass transit, ridesharing, biking and walking will reduce harmful vehicle emissions, while improving the pedestrian and cycling experience at the project. TDM makes a site more accessible to all modes of travel, which can improve its attractiveness and competitiveness to potential tenants and customers. Accomplishing TDM In an urban setting, there are many modes of transportation that can be used as an alternative to the automobile. In a suburban setting, it might be necessary to provide the alternatives (such as shuttle buses to and from transit) or change the way people think about transportation (such as setting up carpools). One TDM measure, marketing/promotion, can be as simple as educating your users to options available such as transit, ridesharing and other means they may not know. Simple education programs, through mailings, flyers, radio spots, etc. have successfully provided shifts in mode choice. Other methods are more intensive, and therefore more costly, such as transit accessibility. A development in the vicinity of mass transit, but not quite within walking distance, may benefit from shuttle or ferry service. These services have proven highly successful in various scenarios where reducing trip time to transit shifts people out of their cars. In some cases, it might be necessary to provide a full scale system to provide a variety of alternatives. These may include methods such as extending transit service to a site and incorporating car sharing. Our firm, Sam Schwartz Engineering (SSE) has worked with our clients to do this successfully for IKEA in Red Hook, Brooklyn, Citi Field in Queens and Prudential Center in Newark. Making transit cheaper is another way to make it more accessible. Fortunately, the federal government has tax policies that allow employers to reduce the cost of transit and vanpool fares. Projects would be well served to help their potential tenants take advantage of the federal tax incentive. In addition, federal funding can be used to help start new transit services for up to three years through the Congestion Mitigation Air Quality (CMAQ) program. SSE has also assisted clients in developing initiatives that take advantage of these federal programs. Parking management is another way to help a project reduce its parking demand and move users into other modes of travel. Providing incentives for high occupancy vehicles (carpools and vanpools) through discounted and/or preferred parking, accommodating parking for car-sharing and market-based parking pricing are a few examples. Whether you are a developer, owner or operator, investigating TDM at the beginning of your project may facilitate approvals, save you cost and help with sustainability. All of this would no doubt be both a benefit to you and your project. Erich Arcement, P.E., PTOE, is senior vice president and Brian Shaw is senior planner and head of the TDM group for Sam Schwartz Engineering, New York, N.Y.