2. The Evolving Role of Demand Management
|CHAPTER ACRONYM LIST
||Active Traffic Management
||Bus Rapid Transit
||Congestion Mitigation and Air Quality
||Department of Transportation
||Federal Highway Administration
||High Occupancy Toll
||High Occupancy Vehicle
||Institute of Transportation Engineers
||The Intelligent Transportation Systems Joint Program Office
||Single Occupancy Vehicle
||Travel Demand Management
||Trip Reduction Impacts of Mobility Management Systems
||Transportation Systems Management
||Vehicle Hours Travelled
||Vehicle Miles Travelled
Few question the need to manage travel demand these days as growth in travel continues to exceed our ability to accommodate it with new capacity. The most recent edition of The Institute of Transportation Engineers (ITE's) Traffic Engineering Handbook concludes: "With a growing understanding of the effects of demand and congestion beyond the right of way, operating agencies, policy makers and the public may employ techniques which may minimize financial, emotional, environmental and physical costs on the individual and on society."4
Around the nation, agencies are getting smarter in how they manage existing infrastructure and in deciding when strategic capacity enhancements should be made in certain situations. For example, many of the capacity enhancements being made are incorporating TDM as a key component, be it high occupancy vehicle (HOV) or high-occupancy toll (HOT) lanes or other more operational components like ramp metering or bus rapid transit (BRT).
When considering past urban transportation planning practices, planners attempted to "predict and provide" or estimate future travel demand based on population and employment projections. Utilizing this information, they worked to build enough capacity to meet this estimated demand. Costs, environmental concerns, time requirements, and various other factors have contributed to our inability to "build our way out" of the congestion problem. However, TDM has the potential to reduce overall travel demand for single-occupancy vehicle (SOV) use, when implemented sustainably and successfully, thus reducing or delaying the total need for capacity expansion. As such, TDM needs to be considered throughout the planning process, certainly well before project selection so that tradeoffs between demand reduction and supply expansion can be carefully assessed. Given the potential for lower costs – decreased environmental and energy impact – and the ability to expand travel choices, TDM may be the preferred solution in many instances. The Swedish Road Administration has institutionalized this process by adopting the "four-stage principle" that requires planners to consider demand management and mode shifting before considering efficiency measures, systems management, or minor road improvements, and new investment or major reconstruction as a last resort.5
This chapter provides a discussion of a new, broad definition for TDM and how it fits into today's management and operation of the transportation system. A new framework is presented on traveler choices within the context of TDM, suggesting that the concept goes well beyond mode choice. The chapter discusses how TDM can be a vital part of efforts to create a more sustainable transportation system. The contemporary view of TDM is also enhanced with advances in technology, making possible dynamic, immediate, and real-time choices. Finally, the economics of TDM are discussed to suggest the significant return on investment that can result from TDM.
2.1 A New Focus on Travel Choices for Reliable Travel
Traditionally, TDM has been narrowly defined as commuter ridesharing and its planning application restricted to air quality mitigation (conformity analysis), development mitigation (reducing trip generation rates and parking needs), or efforts to increase multi-modalism in transportation plans. At the heart of traditional ridesharing are measures to induce commuters to shift to higher occupant modes: carpooling, vanpooling, and transit. It also includes non-motorized modes or active transportation modes, such as bicycling and walking. Finally, traditional ridesharing also includes strategies to move commuters outside the peak congestion periods through work arrangements, such as flextime, telecommuting, and compressed work schedules. Traditional rideshare will continue to play a significant role in the contemporary view of TDM as it seeks to influence travel at the most congested places and times. Extensive guidance and documentation are available on best practices for implementing effective ridesharing programs, including the U.S. DOT's Ridesharing Options Analysis and Practitioner's Toolkit.6
A more contemporary definition of TDM consists of maximizing travel choices, as stated in the definition provided in an FHWA report on TDM:
Managing demand is about providing travelers, regardless of whether they drive alone, with travel choices, such as work location, route, time of travel and mode. In the broadest sense, demand management is defined as providing travelers with effective choices to improve travel reliability.7
This definition of TDM, emerging from an international scan of practices in Europe, incorporates many strategies heretofore not considered within the realm of TDM, such as road pricing, operational strategies that shift travelers' route and time (such as advanced traveler information), and strategies that influence which lane travelers use on a given facility. Contemporary TDM recognizes that improvements to transportation system reliability come not only from system capacity expansion and improvements, but also from travel and TDM.
In a sense, the contemporary definition of TDM is probably closer to the concept of transportation systems management (TSM). The availability of choices not only reduces overall demand (VMT) but seeks to redistribute demand by making efficiency improvements to the road system, thereby potentially reducing vehicle hours traveled (VHT). As a result, the contemporary definition of TDM encompasses a variety of established solutions, including: traditional ridesharing, road pricing, and TSM.
Another key aspect of the definition includes choices for all travel and not just commuting. This may mean providing choices for school travel, special events, specific locations (such as national parks, historical cores), shopping or leisure travel, and highway reconstruction efforts.
Similarly, this definition applies not only to the individual traveler but also to freight. For example, time choice is the key to the Pier Pass program in Los Angeles.8 To address congestion/air quality issues and encourage off-peak truck travel near facilities and I-710, peak period access and egress to port facilities is priced. In this case, location choice is the key to freight consolidation strategies aimed at keeping larger trucks out of the urban core. This has been demonstrated in Europe (using clean vehicles to make deliveries to city center stores).9 Alternately, mode choice was one reason for network-wide truck tolls in Germany, which induced a moderate shift to rail, as well as helping to maintain the road system.
Finally, TDM has always been about forming new partnerships with government agencies that support TDM. Most commonly, this partnership involves the private sector, such as employers, developers, or business organizations seeking cooperative means to serve commuters. Partnerships have also been formed with special interest groups, such as environmental groups, seeking to promote TDM as a strategy to meet mutual goals. More recently, partnerships are forming with private entities that are developing new tools for dynamic demand management, using social media and new technologies. Finally, partnerships are being formed with grassroots organizations aimed at improving the quality of life in a given area and seeking to promote more and healthier travel options. The benefits of these partnerships are many, including resources, policy support, technical assistance, and implementation aid. The adjacent quote by the Utah DOT TravelWise Coordinator, Angelo Papastamos, highlights the benefits of TDM partnerships.
"Travel demand management, or as we call it in Utah "TravelWise," has allowed the Utah Department of Transportation to partner with other state agencies, businesses and large employers, transit providers, local governments and others involved in planning for our region in a proactive manner. In Utah, we have found that if we all do a little, we can do a lot to reduce traffic congestion, improve our environment, and reduce energy needs; all while strengthening Utah's economy."
Angelo Papastamos, P.E. Utah DOT TravelWise Coordinator
A view of contemporary TDM strategies using this notion of choices is illustrated in the following trip-chain graphic (Figure 2.1). At the heart of the conceptual framework is the need to understand the difference between TDM and traffic management. Figure 2.1 shows the need to integrate travel demand and traffic management into a larger framework of travel choices and congestion reduction techniques. These choices begin with consideration of overall travel demand and work their way through traffic demand and network demand. The set of strategies shown on the right side of the figure are not exhaustive and are meant to show the kinds of strategies that focus on traffic management, TDM, or both. However, the key to the conceptual framework is to show differences between types of demands and how offering choices can influence these demands. Each set of demands and choices is discussed below, based on guidance provided by FHWA on integrating TDM and Active Traffic Management.10
Figure 2.1: Travel Demand Management – A Philosophy of Choices
Source: FHWA – Integrating Active Traffic and Travel Demand Management
Stage One – Travel Demand and Mode and Destination Choices
This overall demand can be modulated by influencing traveler choices about whether to travel, which mode to use (car or other mode), and where to travel (the destination). Many techniques can be applied at this stage of the framework to reduce overall travel demand by car. This might include incentives to use higher occupancy modes (e.g., carpool, vanpool, transit) or non-motorized modes (bicycle, walk). It might also include programs to encourage working or shopping from home (addressing whether to travel) or to reduce trip lengths or overall VMT (by combining trips or shopping or working closer to home). Of course, congestion pricing has been proven to be an effective means to reduce travel demand by inducing mode shift and reducing overall peak travel.11 Congestion pricing can come in the form of cordon pricing, such as the pricing schemes in London and Stockholm, or as a fee on all or targeted vehicle usage. Small changes in demand can have significant impacts.
"In our work, we have the opportunity to speak with commuters directly about their commute choices. Research indicates that for commuters, TDM is a key component of the overall range of options they review. Although they might not know the meaning of 'TDM,' they recognize its benefits!"
Karen S. Smith, Senior Vice President of Research Strategy
This stage involves influencing travel demand before the decision to drive (particularly alone) is made. Measures to influence travel mode and destination have the ability to reduce overall traffic volumes on the highway network, and when properly targeted, can reduce traffic volumes on key congested facilities during critical times of the day. The success of TDM initiatives, implemented during and as an integral part of highway reconstruction projects, provides solid evidence of the ability to manage travel demand to reduce overall traffic volumes.
Stage Two – Traffic Demand and Route and Time Choice
Once the vehicle trip demand by car is determined, traffic may be influenced through measures that affect time and route choice (i.e., real-time traveler information) before reaching a congested corridor and/or time period. Choices provided in this stage aim to change the time of day of travel to avoid the most congested periods or to seek alternate routes that might be less congested. This set of choices can also reduce the volume of vehicles using and impacting congested facilities – thus improving operational efficiency. Congestion pricing can also influence the time of day or route that a commuter or other traveler chooses. Most HOT lane projects in the U.S. increase the price of using the facility based on time of day and/or congestion levels. This has the impact of moving travelers to the edges of the peak period or even creating a route or mode shift to parallel facilities or to public transit or other less costly modes, such as carpooling (as mentioned earlier).
Can managing demand have a real, noticeable impact on the highway system?
Consider the situation when relatively minor changes in daily urban activity can have a significant
impact on traffic. Some observers point to the situation where government worker vacations (e.g.,
federal employees in Washington D.C.) or holiday schedules in some states (e.g., unique state
holidays in California and elsewhere) can have a profound effect on recurring, peak period congestion.
This suggests that as little as a 10% reduction in demand can eliminate recurring congestion
in some circumstances (DeCorla-Souza, 2006).
Due to the short-term nature of these reductions, sufficient time is not available to restore equilibrium (when those who have used other travel choices move back to driving alone during the
peak period). This suggests that strategies to "dynamically" manage demand may be effective in
managing traffic while not allowing induced demand to refill freed capacity. In the longer run, efforts
to manage demand need to address issues of induced demand and route diversion that might threaten to refill unused capacity. However, an overall demand-oriented approach would seek to reduce overall demand and modify behavior in ways that do not presume travel time minimization as the principal motivator for all drivers.
Stage Three – Network Demand and Lane Choice
Once a traveler makes the decision to travel on a given facility, network demand has been determined. In this case the final choice that can be influenced is the lane that travelers use on a given facility (and how each lane is used). At this point, the system operator heavily influences traveler choices on a given facility. This concept of influencing lane choice is rather new to the U.S., but is at the core of new operational concepts, such as Active Traffic Management (ATM).12 Two examples of ATM include the use of the hard shoulder and dynamic lane controls. In several European countries, the hard shoulder is being used during congested periods as a travel lane, with safety issues being addressed with active monitoring and incident management. When implementing ATM, lane speeds are also reduced to maintain safe operation of the facility. In this manner, strategic capacity is added when, and only when, needed. Lane choice can also be actively managed during incidents, by slowing cars upstream and moving them into lanes unaffected by the incident. The use of overhead speed and information displays, coupled with real-time monitoring, helps accomplish this by showing motorists the reason for the slowing of traffic upstream.13
HOV and HOT lanes offer users the choice to experience reliable travel times in exchange for increased occupancy or paying a fee on a given facility. HOT lanes offer choices and do not force anyone to change their travel behavior.
Traditionally, many of these strategies are considered TSM, as they serve as an important element in ensuring that choices are sustained throughout the trip chain to ensure a reliable movement of goods and people.
Table 2.1 provides a comprehensive toolkit listing from the ITE Traffic Engineering Handbook on traffic management, TDM strategies, and key travel choices: Route (R), Mode (M), Location (L), Time (T), or origin/destination (OD).14
Table 2.1: Traffic Management and TDM Strategies Influencing Choices
||Traveler Choices Affected
|Arterial Management – The management of traffic signals, dynamic and fixed lane management along surface streets including speed management, pedestrian and bicycle interaction with vehicles, vehicle priority coordination, and coordination with other techniques such as traveler information, electronic payment, or incident management.||R, M, L|
|Freeway Management – The management of lanes along freeway and associated ramps interfacing with the arterials including speed management, and coordination with other techniques such as traveler information, electronic payment, or incident management.||R, M, L|
|Transit Management – Transit service available to a site, personal security, route and scheduling information, and coordination with traveler information services.||R, M, T, OD|
|Incident Management – The detection, response, and recovery from events that are non-recurring, providing information to response personnel and the public, minimizing the impacts on traffic flow, and optimizing the safety of the public and responders.||R, L, T, OD|
|Emergency Management – Hazardous material routing and security management, routing, coordination of emergency response service providers, and information dissemination and coordination.||R, M|
|Road Pricing and Electronic Payment – Payment services and systems associated with toll facility operations, variable pricing, VMT fees, parking facilities, and transit services.||R, M, L, T, OD|
|Traveler Information – Pre-trip, Near Pre-Trip, and en-Route information provided to the traveler via roadside, in-vehicle or personal communication devices on the current travel conditions, trip planning services, tourism, special events, and parking information.||R, M, L, T, OD|
|Roadway Operations and Maintenance – The management of work zones and route closures through the use of traveler information, lane and speed management systems, and enforcement and response service providers.||R, L, T, OD|
|Road Weather Management – Planning for and responding to weather events impacting traffic operations and roadway conditions, information distribution to travelers and response personnel, and operations of facility under inclement conditions.||R, M, L, T, OD|
|Commercial Vehicle Operations – Clearance and screening of commercial carriers to optimize flow of goods and services while optimizing safety and efficiency through the use of roadside and in-vehicle technology.||R, L, T|
|Intermodal Freight – Integrated operations of freight transported by multiple modes both internationally and domestically.||R, M, L, T, OD|
|Parking Management – Parking information, variable pricing, routing to available parking.||M, T, OD|
|Quality Pedestrian Movement – Availability of pedestrian facilities that are integrated within the overall transportation network and accommodate or even promote non-motorized travel.||R, M, T, OD|
|Amenities On-Site – Bicycle locks, showers, automated teller machines, vanpool or carpool parking, local shuttle service, infrastructure for teleworking.||M, T, OD|
|Ridematching Program – Carpools, vanpool programs, preferred parking, transit or parking subsidies.||R, M, L, T, OD|
|Alternative Work Schedules – Four 10-hour days per week, staggered hours, flexible hours.||R, M, L, T, OD|
|Telecommuting Options – Work environment that supports employer-employee relationship from remote sites with consideration of accessibility, accountability, and productivity.||R, M, T, OD|
|Travel Plans – Worksite, school, or event plans that incorporate travel demand and traffic management strategies to reduce the negative impacts of car use to the site.||M, T, L, OD|
|On-Site Travel Coordinator – Staff and services focused on travel services and demand management strategies. ||R, M, T, OD|
2.2 A Vital Tenet of a Sustainable Transportation System
As illustrated by this conceptual framework and discussion of choices, TDM is less about certain management strategies and more of an operational philosophy that seeks a holistic approach to urban transportation -- one that better balances demand and supply solutions, one that seeks to make better use of existing capacity, and one that seeks to do so in a more sustainable manner. One study describes this broader conceptualization of TDM as follows:
But travel demand management is a much broader concept than that assigned to
mobility management or ridesharing. Implicit in the use of the term is the assumption
that it is accompanied by the implementation of sustainable mobility, introduction of full
cost pricing and organizational or structural measures to ensure a broad range of
complementary interventions work effectively together to realize the benefits of sustainable transport. It is the unifying philosophy of TDM, not specific measures associated with it,
that underpins the policy objective of a more sustainable system of transport. Perhaps this philosophy is better understood simply as 'urban transport management' - i.e. obtaining a
more appropriate balance in favour of needs over wants. Put simply, where transport used
to be supplied to accommodate travel demand, travel must now be managed to use the
available transport supply most efficiently.15
Transportation systems can be better managed and characterized by
- Expanding the supply and availability of (more sustainable) alternatives.
- Integrating demand-side strategies into operational efficiency initiatives.
- Controlling demand for the use of unsustainable modes.
- Providing incentives and rewards for undertaking sustainable travel habits.
- Imposing full-cost pricing on the use of the automobile.
TDM has many opportunities to promote sustainable transportation. Broadly, by offering choices, TDM becomes a value proposition for areas to reduce their dependence on SOV travel.
Potential Opportunities for TDM to promote sustainability:
- TDM reduces the need for new or wider roads
By persuading people to drive less often, to closer destinations, outside of rush hours or using less busy routes, TDM can reduce the demand for new road infrastructure.
- TDM makes personal travel decisions more efficient
Many drivers make travel decisions based on poor information and a lack of experience with non-automobile options. TDM improves their awareness and understanding of options, and their willingness to try them.
- TDM maximizes return on infrastructure spending
Studies have shown that good information can significantly increase ridership on new transit infrastructure and services. Likewise, reducing overall travel demand on highways adds to the effective lifespan of strategic capacity improvements.
- TDM makes the most of our current assets
It saves people money and time by helping them make efficient travel decisions. It improves health by promoting physical activity and less-polluting modes. It benefits employers by increasing productivity, reducing parking costs, and helping to attract and retain workers. It promotes economic development by reducing congestion and enhancing worker mobility.
- TDM is a versatile and dynamic management tool
TDM measures can be customized for specific audiences (e.g., business park commuters), destinations (e.g., major hospitals), travel modes (e.g., cyclists), travel corridors (e.g., a busy highway), trip purposes (e.g., school) or specific timeframes (e.g., major events). TDM strategies can be delivered in months, rather than years.
- TDM initiatives have multimodal benefits
It recognizes that people see alternatives to driving as a "suite" of options. Non-drivers tend to be public transport users, carpoolers, pedestrians, or cyclists at different times, for different reasons. TDM expands travel choices within this suite of options.
- TDM works at the scale of individuals, but has huge power across a community
If every person who drives to work in a community decided to leave their car at home just one day a month, the 5% reduction in commuter traffic could significantly ease daily congestion.
2.3 Technology and Connectivity Driven
Contemporary TDM is also characterized by a heavy reliance on technology and communication systems. Personal and social connectivity through communications is rapidly changing the way we travel and why we travel. The world of traffic management has changed in response primarily to the explosion of the scope and the capability of communication technologies enabling a previously unimaginable level of connectivity. Broadly, the Intelligent Transportation Systems Joint Program Office (ITS-JPO) has defined connectivity as an important theme in their strategic plan for 2010-2014:
[Connectivity is] a concept that is rapidly changing our daily habits: real-time information gives us the power to make decisions and act on opportunities, provides us with details
needed to understand our fast-paced world, and brings us an awareness of how our
systems work. The start of the 21st century introduced advanced wireless technologies to
our lives, and already they are having a dramatic impact on our connections to family, friends,
and the social and entertainment worlds. These technologies are proliferating throughout
the business, political, and educational arenas, changing our relationship to information and creating an awareness of situations that previously would have gone unnoticed. These technologies are redefining how we access knowledge; for the realm of transportation, this means unprecedented awareness about what is happening to and throughout our transportation system at all times.16
, this has meant that existing approaches can now be enhanced and provided using new technologies and tools. Some non-exhaustive examples of the linkage between technology and TDM
include the following:
- Advanced travel time information can now impact trip decisions in a much more comprehensive manner using new media (such as Facebook and Twitter), new sources of data (vehicle probes, crowd sourcing) leading to new information (comparative travel times, predicted travel times, real-time parking availabilities).
- Dynamic ridesharing approaches are starting to emerge, taking into account social networks.
- Personalized travel information via SmartPhones allows for better pre-trip planning by integrating real-time information from various traffic and transit systems.
- New mobility applications such as connection protection greatly increase the traveler's choices.
TDM has always been a user-driven industry. With these new tools and technologies, contemporary TDM can expand the scope, functionality, and application markets for a majority of market strategies to a greatly increased user population.
2.4 Economics of TDM
One issue that arises for planners seeking to integrate TDM into the planning process is how to "sell" TDM, since the use of non-SOV travel options is largely perceived as inconvenient and inferior. A first response might involve the realization that many travelers want more choices that have the potential to be faster, cheaper, and of higher quality than driving alone.
Cost often wins the debate for TDM, as TDM strategies offer the following benefits in terms of costs and cost effectiveness:
- TDM offers travelers lower cost options to driving alone.
- TDM allows considerable cost savings for travelers over time.
- TDM strategies are generally low cost as compared to capital projects, or can reduce the overall cost of integrated projects.
- TDM is a cost-effective means to meet key policy objectives.
- TDM strategies have very favorable benefit to cost ratios.
The first two points are fairly well accepted, that by sharing rides, riding transit, bicycling, and walking, travelers can save money over driving alone, even when considering only the perceived out of pocket costs of operating a vehicle. Over time, these savings can add up and most regional commute management websites include a "commute cost calculator" to show commuters prospective savings. However, the latter three points deserve additional discussion.
TDM Strategies are Low Cost for Meeting Mobility Solutions
In general, the budgeted amounts allocated for TDM are considerably less than more capital-intensive and operational projects. For example, the TDM portion of the T-REX highway reconstruction and light rail project in the Denver region was $3 million of a total $1.67 billion project. But the key question is whether TDM strategies fulfill mobility and accessibility needs commensurate with the money invested.
"Nothing is more cost effective than TDM. "
Harold W. Barley N – Executive Director, MetroPlan Orlando
One program evaluation of the rideshare program in Los Angeles County17 compared the cost effectiveness of the rideshare program to rail improvements planned for the region, both intended to enhance mobility options in the region. The cost per trip reduced and the cost per person placed into the rideshare program were compared to forecasts of the cost per new rider on a proposed light rail extension. The cost per trip reduced was $2.80 for the rideshare program and the cost per person placed into a new ridesharing arrangement was $0.82 per day. The comparative cost per new light rail rider per day was $6.94 to $7.77 in capital costs and $2.66 to $2.99 in operating costs.
TDM Strategies are Comparatively Cost Effective in Meeting Policy Objectives
Similarly, TDM strategies have been shown to be a cost effective means of meeting key policy objectives. One study of projects funded by the Congestion Mitigation and Air Quality (CMAQ) program (reported in detail in Chapter 10) concluded that TDM measures were among the most cost effective in reducing automobile emissions. The analysis showed that as a group, traffic flow projects received 33% of all funds, but resulted in a cost per pound of emissions reduced of $42.70. Rideshare programs accounted for only 4% of all funds, yet reduced a pound of emissions for $10.25. Likewise, miscellaneous TDM programs accounted for 3% of all CMAQ funds but reduced a pound of emissions for $7.66.18
Other studies tie cost effectiveness solely to the value of a vehicle trip reduced, as that used by Washington State DOT (WSDOT) to select TDM projects for funding. WSDOT sets the value of a trip reduced at a maximum of $460.00, equal to that possible using tolling. Therefore, any TDM project that removes a vehicle trip for less than that is considered cost-effective. As such, WSDOT approved 17 TDM projects in 2006 valued at $1.3 million to purchase 3,831 daily vehicle trips, at a cost of $339.00 per trip removed.
TDM Strategies Generate Good Benefit/Cost Ratios
Several research projects have developed methodologies to calculate the costs and benefits of TDM in order to allow for objective project selection and evaluation. In seeking to create evaluation procedures for TDM that would produce values comparable to road projects, the New Zealand government developed a procedure that included the following benefits and costs when evaluating TDM measures:19
- Travel time saving.
- Vehicle operating costs.
- Parking costs.
- Health benefits of cycling and walking.
- Public transit fares.
- Congestion reduction.
- Walking and cycling costs.
- Accident costs.
- Public transportation costs (if expanded).
- Externality costs.
Applying such a methodology to an individualized marketing program in South Perth, Australia, resulted in Benefit to Cost Ratios of 13:1 (and 15:1 when factoring in reduced accidents).20
Similarly, the Trip Reduction Impacts of Mobility Management Systems (TRIMMS) model (see Chapter 9) developed at the Center for Urban Transportation Research includes a module to calculate the benefit/cost ratios for TDM strategies using a similar approach. The TRIMMS model allows for the estimation of trip reduction impacts for TDM strategies applied to a given situation and from that, the ability to calculate the value of the trips reduced and the benefit to cost ratio. One exemplary test of the model for a commute-trip transit fare reduction shows the net value of each vehicle trip reduced to $645.00 and a peak period benefit/cost ratio of 2.8.21
Colin Black and Eric Schreffler, "Understanding TDM and its Role in the Delivery of Sustainable Urban Transport" Transportation Research Record 2163, pp. 81-88, 2010.
Commercial Transport in European Cities: How do European cities meet the challenges of commercial transport? Experiences and case studies from the CIVTAS Programme of the European Commission, Hans-Joachim Becker, Diana Runge, Urte Schwedler, Michael Abrahamm, Berlin, July 2008, available at http://www.civitas-initiative.org/docs1/IVP_21.pdf, ISSN 1613-1258
DeCorla-Souza, "Improving Metropolitan Transportation Efficiency with FAST Miles," Journal of Public Transit Research, Vol. 9, No 1, 2006.
FHWA, "Active Traffic Management: The next step in congestion management," Report No, FHWA-PL-07-012, July 2007
FHWA, Integrating Active Traffic and Travel Demand Management: A Holistic Approach to Congestion Management, prepared by ESTC for the International Technology Scanning Program, FHWA-PL-11-011, 2011, http://international.fhwa.dot.gov/pubs/pl11011/pl11011.pdf
FHWA, Congestion Pricing: A Primer – Overview, FHWA-HOP-08-039, 2008, https://ops.fhwa.dot.gov/publications/fhwahop08039/cp_prim1_00.htm
FHWA, Office of Innovative Program Delivery, "Road Pricing Defined: VMT Fees," https://www.fhwa.dot.gov/ipd/revenue/road_pricing/defined/vmt.htm
FHWA, Mitigating Traffic Congestion—The Role of Demand-Side Strategies, prepared by ACT, Report No. FHWA-HOP-05-001, October 2004.
FHWA, "Managing Travel Demand: Applying European Perspectives to U. S. Practice," Report No. FHWA-PL-06-015, May 2006.
LDA Consulting. LACMTA Rideshare Evaluation Project: Task 7 -Comparative Cost Effectiveness. Los Angeles County Metropolitan Transportation Authority, April 2002.
Maunsell, P. R. a. B. A. H. , Travel Behaviour Change Evaluation Procedures- A Technical Report. 2004, Transfund New Zeland/EECA: Melbourne, Australia.
National Center for Transit Research, Economics of TDM: Comparative Cost Effectiveness and Public Investment, NCTR 77704, March 2007.
Office, A. G. , Evaluation of 26 Australian TravelSmart Projects in the ACT, South Australia, Queensland, Victoria, and Western Australia. 2006, Department of Environment and Heritage: Canberra, Australia.
Transportation Research Board. The Congestion Mitigation Air Quality Improvement Program: Assessing Ten Years of Experience. Special Report 264. National Academies, 2002.
ITS-JPO (2010), ITS Strategic Plan, 2010-2014: Transforming transportation through connectivity, retrieved from http://www.its.dot.gov/strategic_plan2010_2014/index.htm
ITE, Traffic Engineering Handbook: 6th Edition, edited by Walter Kraft, 2009.
USDOT, Volpe Center, Ridesharing Option Analysis and Practitioner's Toolkit, prepared for FHWA, 2010, http://www.planning.dot.gov/documents/RidesharingOptions_Toolkit.pdf.
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