What is TDM?

TDM Options“Transportation demand management” is the flip side of infrastructure. It focuses on helping people use the infrastructure in place for transit, ridesharing, walking, biking, and telework. It is cost-effective in guiding the design of our transportation and physical infrastructure so that alternatives to driving are naturally encouraged and our systems are better balanced.

TDM thus underlies most of the important new initiatives of today: transit-oriented development, complete streets, walkable activity centers, livability and sustainability initiatives, and integrated corridor management.

TDM, focused on people first, functions on two levels.

At its most basic level, TDM is a program of information, encouragement and incentives provided by local or regional organizations to help people know about and use all their transportation options to optimize all modes in the system – and to counterbalance the incentives to drive that are so prevalent in subsidies of parking and roads.  These are both traditional and innovative technology-based services to help people use transit, ridesharing, walking, biking, and telework.

There is also a deeper dimension of TDM that is equally important.  TDM is a principle that should guide everything we do in designing our transportation and physical infrastructure so that alternatives to driving are naturally encouraged and our systems are better balanced.  TDM thus underlies most of the important new initiatives of today:  transit-oriented development, complete streets, walkable activity centers, livability and sustainability initiatives, and integrated corridor management, to name a few examples.

TDM graphicWhen we put these two together and offer robust TDM services in conjunction with properly designed infrastructure, we get the largest impacts and the biggest bang for our buck.

Further Reading:

Arlington’s measurement of its TDM goals looks like this:

Arlington TDM Goals


















County Bureau Gets Creative Moving People Instead of Cars

JUNE 4, 2014

Arlington County Commuter Services (ACCS) looks and operates more like a start-up tech company than a government agency.

The transportation demand management (TDM) arm of the Virginia county has an energy one might not normally expect in a government office.

Busily decorated with site plan documents pinned to walls, bookcases filled with business management paperbacks, and a prop Capital Bikeshare bike located centrally amidst the cubicles, one could infer from the controlled chaos that this is an organization valuing innovation and creativity.

The innovation occurring at ACCS, says Bureau Chief Chris Hamilton, is “the robust application of transportation demand management, or TDM.”

TDM is a group of strategies that incentivizes and enables alternative modes of transportation — biking, walking, and transit, among them. These techniques are especially important for a county like Arlington, one of the densest places in the country, with borders that burst each day with the highest proportion nationally of non-residents commuting into the county for work.

TDM is a way to deal with this potentially crippling transportation problem in a way that makes sense both fiscally and from a land-use perspective. It is a way to get more utility out of the infrastructure in which a locality has already invested, and a way to get more bang for the taxpayers’ buck.

Here’s a roundup of the key ways TDM works in Arlington:

  • Employer and Residential Services. Arlington Transportation Partners (ATP)manages what can be considered the “bread and butter” of TDM, according to program manager Wendy Duren. Using the business-to-business model, ATP works directly with employers and multi-family residential property managers to extend transit benefits to employees and residents, which hopefully leads to different commuting behaviors. These services benefit employers in particular because of the positive impact it makes on companies’ bottom lines. Kevin Shooshan, principal of the Shooshan Company, said that reducing commute times is important because, “from an employer perspective, it’s about efficiency of my employees and of my costs,” Studies show that shorter commutes are associated with increased productivity.
  • Site-Plan Enforcement. The average lifespan of a building is 73 years – though some structures like the iconic Pentagon (completed in 1943) will persist much longer than that. Through its site-plan process, Arlington may permit a developer to deviate somewhat from specific zoning requirements – to build at a greater density (and greater profit), for instance. In exchange, the developer agrees to certain conditions, including remediation of the congestion that will be produced by this building over its long lifespan. This enforcement arm of TDM is not simply a top-down application of government bureaucracy, but has proven to be predictive of market trends. Bike parking, for instance, started out in Arlington as a TDM requirement imposed upon developers. Recently, however, the amenity has become embraced by developers like Sia Madani of Madison Investments, whose new D.C. project Elysium 14 will be built entirely without automobile parking, in favor of the bicycle parking more consumers are demanding. In addition to payment of fees to support TDM activities in the county, Arlington also guides the developer in constructing amenities such as bike parking facilities, which are crucial in encouraging cycling.
  • CommuterDirect.com. With sales of $44 million in the county’s most recent fiscal year (July 2012 to June 2013), CommuterDirect.com transit fare sales have risen rapidly since 2009. Commissions from CommuterDirect.com’s sales account for about one-third of the ACCS budget, so is considered a critical source of funding for the bureau.
  • Commuter Stores. Arlington’s Commuter Stores (four in Arlington, one in Maryland, and one mobile store that travels throughout the region) were created with the knowledge that, while online sales are great, some people prefer the personable touch. Person-to-person sales are achieved through these stores, which sell transit media for all the major D.C. jurisdictions. The Commuter Store high-satisfaction ratings prove that the system is working well: more than eight in 10 of Commuter Store customers surveyed in 2012 indicated that they would definitely return to the Commuter Store for future purchases. With the Rosslyn store moving to a new prime location street side in the Rosslyn mall, big changes are coming for the highly-rated stores.
  • Capital Bikeshare. Arguably the most successful bikesharing system in the United States, if not the largest, most people aren’t aware that Capital Bikeshare (CaBi) began as an initiative of ACCS. CaBi is famous in transportation circles for its ability to recover a majority of its operational costs, an enormous feat compared to other forms of transportation. Lest users be confused about these bikes’ intended use, exponentially increasing fees discourage trips longer than would be required to perform a “last mile-first mile” connection. As CaBi program manager Paul DeMaio explains, “Capital Bikeshare is not bicycle rental, it’s bicycle transit.”
  • BikeArlington and WalkArlington. Arlington doesn’t have room to build more roads, and its transit capacity, while expanding, is constrained. The county understands that getting its residents to bike and walk is an important strategy in moving people without adding congestion. Facilitating these transportation modes yields a big payoff for local governments: one report has shown that investments in cycling and walking return up to $11.80 for every $1 spent. Pedestrian and bicycle activity on streets and sidewalks creates vibrant, livable neighborhoods that residents prefer. The BikeArlington team is passionate about what they do, with each member biking to work each day (up to 8 miles one way). Biking is hot in Arlington right now, and the county’s commitment to biking is highlighted to great effect in BikeArlington’s documentary BikeSwellWalkArlington walks the walk every day, as well, fulfilling its mission to “get more people walking in more walkable places more of the time” – whether by promoting its popular series of Walkabouts, supporting safe routes to schools, or advancing Arlington County’s national Gold-Level Walk Friendly Community designation.
  • Mobility Lab. Arlington’s commitment to innovation is perhaps best noted in the hand the county had in creating the website you see before you. A news service and marketing tool hybrid, Mobility Lab is the communications and research arm of ACCS. Utilizing an army of more than 80 contributing writers, the Mobility Lab website aims to educate and inform readers about alternative modes of transportation. In so doing, Mobility Lab hopes to also influence commuting choices. Former head of the U.S. Department of Transportation Ray LaHood has recognized the uniqueness of its mission, calling for the need for “more Mobility Labs.”
Arlington County office transit screen

A transit screen from Redmon in the lobby of Arlington County’s headquarters.

Bureau Chief Hamilton describes TDM as a way that “ACCS leverages the investment Arlington has already made in the infrastructure by getting more people to use it.” In a competitive marketplace, with more cities and counties engaging in transit-oriented development (TOD) and competing with Arlington on place, the suite of TDM services provided by Arlington County may be an advantage the county has over other comparable places.

Through innovation and rigorous application of the principles of TDM, ACCS is helping to disprove the maxim that congestion is always a symptom of a region’s success. One commuter at a time.

Office photo by Paul Goddin. Transit screen photo by BeyondDC.

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