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Subjects › Transportation › Transportation Demand Management (TDM)
Updated 12/2011

Transportation Demand Management (TDM)

Contents

Introduction

Congested streets and roadways result when too many people want to drive on the same routes at the same time, particularly during peak commute hours or special events. The term "demand" refers to the amount of street/road use during a given time period. Transportation Demand Management (TDM) programs focus on changing or reducing travel demand, particularly at peak commute hours, instead of increasing roadway supply. Thus, TDM makes more efficient use of the current roadway system. With the right incentives (or disincentives) travelers may be influenced to use transportation systems in a way that contributes less to congestion. In fact, research around the country indicates that well-designed TDM programs can reduce vehicle trips by as much as 30 or 40 percent (as noted in the National Transportation Library article below). Travelers base their travel choices on a number of important motivators including the desire to save time and money, to reduce stress or to improve convenience. At least some of these motivations must be addressed to encourage a change in habits. Some of the most promising TDM programs emphasize coordination with local employers on measures such as car or vanpooling programs, bus pass subsidies, alternative work schedules, telecommuting options and parking management. Studies also indicate that congestion pricing is an especially effective approach, which should gain favor as congestion worsens and new variations on the concept are developed. The sections below describe and provide examples for various types of TDM strategies.

Transportation System Management (TSM) programs constitute a separate but closely related set of strategies, although sometimes included under TDM. Rather than address demand, TSM programs focus on making our transportation systems more efficient. They emphasize getting the most capacity out of roads and other transportation improvements, thus reducing the need for expensive new facilities. For instance, improved traffic signalization can effectively increase the capacity of streets, and bus turnout lanes or faster response to breakdowns or clearing of accidents can significantly reduce delays. A separate Transportation System Management webpage will address these types of strategies.

General Guidebooks and Resources

Articles and Reports

Employer-Based Transportation Programs

Employer-based programs can be among the most effective of transportation demand management (TDM) programs, in part because the program can be tailored to the commute needs of employees at their specific place of work. Employers can provide opportunities for employees to escape a congested commute through options such as alternative work schedules or telecommuting. Employers are also in a position to influence employee commute choices with incentives (such as a subsidized bus pass) or even by removing/reducing subsidies that encourage drive-alone commutes (such as the provision of unlimited free parking). Research indicates that financial incentives and disincentives such as these are particularly effective commute trip reduction measures. Numerous studies conclude that parking charges, telecommuting, flexible work hour provisions including compressed work weeks, guaranteed ride home programs, and incentives for biking and walking all can be effective in reducing drive alone commuting. In addition, programs that encourage carpooling and vanpooling have proven successful in a number of localities, particularly if vans are provided.

Washington State's Commute Trip Reduction Program

Washington State's Commute Trip Reduction (CTR) Program, in effect since 1991, is the first statewide employer-based transportation demand management program in the country. The goals of the program are to improve transportation system efficiency, improve air quality, and to conserve energy through employer-based programs that encourage employees to find alternatives to drive-alone commuting. The success of the program depends on collaboration between local governments, employers and the Washington State Department of Transportation (WSDOT).

The CTR law applies to all employers that have 100 or more full time employees who work at a single worksite and begin work between 6 and 9 a.m. on two or more weekdays for at least 12 continuous months. Only employers in counties with 150,000 or more residents must participate - currently those counties are Clark, King, Kitsap, Pierce, Snohomish, Spokane, Thurston, Whatcom and Yakima counties. The CTR requirements also apply to all state agencies and to local governments where at least one employer, meeting the above criteria, is located.

All counties and all local jurisdictions within these counties having at least one such employer must adopt a CTR ordinance to implement CTR goals and requirements within each jurisdiction. The CTR ordinance specifies what actions these large employers should take to encourage employees to choose alternatives to drive-alone commuting. The WSDOT Employee Transportation Coordinator Manual (Adobe Acrobat Document) - Explains what must be included in the employer-based programs and provides other basic information.

The Legislature passed the Commute Trip Reduction (CTR) Efficiency Act (ESSB 6566) (Adobe Acrobat Document) during the 2006 session based on recommendations from the CTR Task Force 2005 Report to the Washington State Legislature (Adobe Acrobat Document). Major changes include 1) establishing a state CTR planning framework that will better integrate with local, regional and state land use planning and investment, 2) providing for local designation of "growth and transportation efficiency centers" that would receive priority in regional funding and for state competitive grants, and 3) streamlining the CTR Task Force into a smaller, more policy-oriented CTR Board.

Commute Trip Reduction Programs and Codes

Other States

Commuter Trip Resources

Work Schedule Changes

Flexible work schedules allow employees to commute to work at less congested times of the day and to make schedule adjustments to better fit their lifestyles. Flextime, compressed work week, staggered shifts, and job-sharing are types of alternative schedules discussed in materials in this section.

Traffic Information

Timely information about current traffic conditions can alert commuters and divert some trips away from developing bottlenecks, where traffic accidents or other incidents are causing delays.

  • Managing Demand Through Travel Information Services,Federal Highway Administration - This brochure highlights the opportunities and benefits for using traveler information services to manage demand during periods of congestion, including congestion during commute periods, special events, and emergencies. It highlights examples of traveler information systems in use around the country and overseas
  • Real Time Traveler Information, Federal Highway Administration publications
  • TravInfo, San Francisco Bay Area partnership between Metropolitan Transportation Commission, the California Highway Patrol (CHP), and the California DOT - One-stop, toll-free phone and Internet service that provides real-time traffic and airport information, and information about transit bike routes and other alternatives
  • Washington State Traveler Information and Travel Alerts, Washington State Department of Transportation - Provides real-time information about traffic conditions allowing drivers to choose other routes or schedules

Traffic Management - Incidents, Special Events & Construction Projects

Sports events, street fairs, political demonstrations, promotional events or other special events can temporarily overwhelm streets and other transportation facilities. Traffic incidents and road construction projects can create lengthy traffic delays. Advance planning, mitigation programs and effective public notice can ease congestion and allow motorists to choose alternate routes.

Congestion Pricing Policies

Congestion pricing, also called value pricing, is a strategy where transportation system users are charged for their use of transportation facilities. Congestion pricing differs from the type of road and bridge tolls that have been used for years in this country to raise revenues to pay for new roads, bridges or other transportation facilities. Instead, congestion pricing is used to manage demand, and to reduce vehicle emissions and gas consumption related to idling engines. A widely discussed approach is to impose fees on drivers in congested areas that may vary depending on time of day, distance traveled, number of vehicle occupants, or location. Similar to the concept of "early bird" dining specials, "red-eye" or off-peak flights, or matinee movie shows, this strategy can encourage those travelers who have flexibility to shift trips to less congested times or routes. A second basic approach, which is gaining attention, is to offer motorists the opportunity to pay a premium for travel via a faster, less congested lane. Although viewed by some critics as catering to the well-heeled, U.S. pilot programs indicate that motorists of all income levels will take advantage of the fast lane, when pressed for time. Delays associated with traditional toll booths can obviously be counterproductive. However, prepayment approaches and new technology to monitor usage, can now be used to more efficiently assess fees.

The Value Pricing Pilot (VPP) program, initially authorized in the Intermodal Surface Transportation Efficiency Act (ISTEA) as the Congestion Pricing Pilot Program, was renewed with the passage of the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). This program encourages implementation and evaluation of value pricing pilot projects to manage congestion on highways through tolling and other pricing mechanisms. This is the only program that provides funding to support studies and implementation aspects of a tolling or pricing project.

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