The Fuel Tax and Alternatives for Transportation Funding: Special Report 285 (2006)

Paul A. Sorensen and Brian D. Taylor

Institute of Transportation Studies, University of California at Los Angeles

Many public officials and transportation analysts are concerned with what they perceive to be the waning buying power of the motor fuels tax. Because the tax is levied on a per-gallon basis, revenues do not rise and fall with fluctuations in inflation or vehicle fuel economy. Given the partisan political climate in which it has grown increasingly contentious to propose increased taxes, many are pessimistic about the prospects for significant increases in state or federal motor fuels tax levies in the years to come. Indeed, the occasional increases in state and federal motor fuels taxes in recent decades have fallen far short of keeping pace with the combined effects of inflation and gains in fuel economy over the same period. On the other hand, annual vehicle miles traveled in the United States have continued to skyrocket for a wide variety of reasons, including population growth, increased affluence and vehicle ownership, greater participation of women in the workforce, and increasingly decentralized metropolitan land use patterns, among others. These increases in vehicle travel have exacerbated both congestion of and wear and tear on roads, leading to calls for increased spending on the construction of new roads as well as on the maintenance of existing roads. The result has been a

widening gap in many parts of the country between highway spending needs and available revenues. In the absence of significant fuels tax increases in the coming years this gap is likely to widen further, a trend that may accelerate in coming years with the gradual introduction of alternative-fuel vehicles that pay less, or even no, motor fuels taxes.

In response to these challenges, the Transportation Research Board convened a special Committee for the Study of the Long-Term Viability of Fuel Taxes for Transportation Finance. One of the many charges to the committee was to investigate the potential for a system of distance-based user fees [using recently developed electronic tolling technologies such as on-board computers, Global Positioning Systems (GPS), digital jurisdiction and road network maps, and wireless communications] to eventually replace fuels taxes. To inform their deliberations, the committee commissioned the authors of this report to perform an extensive review of innovative electronic tolling applications around the world. This review included projects already in operation as well as those that have been proposed or are in the advanced stages of planning; each was evaluated in terms of policy, technology, and political acceptance issues. This report summarizes the results of this research.

In selecting case studies to review for this research, we focused on applications that involve networkwide road use metering and tolling, as we judged these to be the most relevant to the concept of distance-based user fees. As a secondary focus, we reviewed facility congestion toll projects and cordon toll projects that might be relevant from a political or technical perspective. We did not examine standard (time-invariant) toll projects that incorporate simple electronic tolling devices (such as in-vehicle transponders), given that such projects would likely offer little technical or political guidance in the design of a comprehensive distance-based user fee system.

Within the context of the study, the goal was to address three principal questions. First, where in the world have such innovative systems been proposed, planned, or developed? Second, how have these projects and proposals been structured in terms of technical design, institutional issues, and political considerations? Third, what is the current status of the projects and proposals, and what factors have aided or impeded their implementation?

In terms of methodology, possible case studies were identified and investigated for inclusion. The scan was based on a review of the literature, a comprehensive search for documents on the World Wide Web, and several phone interviews with experts in the field. The next step was to compile a set of detailed case studies for

those projects deemed politically and technically relevant to the question at hand. Each detailed case study considered the following topics:

• Stated and implicit objectives of the system;

• Techniques of metering road use and collecting fees;

• Pricing policies;

• Governance;

• History and political setting;

• Experience with public acceptance or rejection;

• Financial structure; and

• Summary of any evaluations that have been conducted for the project or views of those involved with the project, or both.

Once the case studies were compiled, the final step was to compare and contrast the different projects in order to provide perspective on the prospects for implementing a comprehensive distance-based user fee system, including the advantages and the likely obstacles to such an approach. The synthetic analysis was divided into five main sections:

• Policy and pricing issues,

• Technical issues,

• Institutional governance issues,

• Implementation issues, and

• Public and political acceptance issues.

Given the motivations for the study discussed above, the review focused on five distinct types of pricing applications. These included single-facility congestion tolls, cordon (or area) congestion tolls, weight-distance truck tolls, distance-based user fee proposals, and distance-based price-variabilization (e.g., insurance-by-the-mile) studies. In total, 88 different pricing schemes—either operational or in the advanced stages of research or planning—around the world were identified that fell into one of these categories. Of these, 20 were selected for detailed review—specifically, those that were considered to be technically and politically relevant to the question of distance-based user fees.

Ultimately, none of the facility or cordon congestion tolls identified in the initial survey (such as the central London program) were selected for the set of

detailed case studies, because none of these uses a technology platform that potentially could be extended to implement a distance-based user fee program. On the other hand, many of these applications are already operational, and they certainly entail innovative pricing schemes in transportation finance. For this reason, there are occasional references made to relevant findings from such projects within the policy and political acceptance sections of the synthetic review. Most of these observations are drawn from the following projects, all of which have been operational for at least two years:

• Facility congestion tolls: I-15 HOT lanes, SR-91 HOT lanes, Katy HOT lanes; and

• Cordon congestion tolls: London, Singapore, Norway (Trondheim, Oslo).

For weight-distance truck tolls, distance-based user fee proposals, and distance-based price variabilization studies, most of the projects identified were included as detailed case studies. Although many of the truck tolls are already operational, most projects within the other two categories are still in the planning or demonstration trial phases. The specific set of case studies reviewed includes the following:

• Australian “Austroads” truck monitoring proposal (planning phase),

• Austrian “GO” truck toll (operational 2004),

• Bristol truck toll/cordon toll (trial completed),

• German “Toll Collect” truck toll (operational 2005),

• Swiss “HVF” truck toll (operational 2001), and

• U.K. truck toll (planning phase).

• CWARUM, a conceptual proposal by Daniel Malick;

• University of Iowa study (trial pending);

• Oregon Department of Transportation study (trial pending); and

• Puget Sound Regional Council study (trial ongoing).

• ARMAS Pan European Tolling Project (trial ongoing),

• Copenhagen demonstration project (trial completed),

• Gothenburg demonstration project (trial completed),

• Helsinki modeling study (study completed),

• Netherlands “Mobimiles” proposal (canceled 2002), and

• Newcastle on Tyne research project (study completed).

• Atlanta variable insurance study (study ongoing),

• Minnesota “PAYD” study (study ongoing), and

• Progressive Insurance study (study ongoing).

Collectively, the pricing projects that were examined incorporate a wide range of policy objectives, though the specific goals tend to vary depending on the type of application. Table 1 provides a list of the most common stated and implicit objectives and indicates the most relevant policy goals for each category of projects. Note that an entry of “primary” indicates that the objective is one of the driving motivations behind most or all of the projects within a given category, while an entry of “secondary” indicates that the goal was identified explicitly in only a minority of the projects reviewed. Note also that under the category of distance-based road user fees, several of the objectives (such as reducing demand for travel by increasing its marginal cost or encouraging the adoption of lower emission vehicles

through appropriate fee offsets) are considered by the project developers to be of primary importance for the international projects but only of secondary importance for those in the United States.

In addition to policy objectives, the projects studied also exhibit considerable variation in terms of the travel characteristics to be metered and priced. At the highest level, these characteristics can be divided into four separate categories. First, each of the projects includes, at a minimum, a measure of total distance traveled (which is not surprising, given the selection criteria through which the projects were chosen). Second, a number of the projects also consider the time of travel, either for the application of congestion toll surcharges during hours of peak travel or for the enforcement of operating regulations (in the case of trucks only). Third, most of the projects also incorporate some determination of the location of travel. In the simplest case, this might be limited to geographic area, for the basic identification of separate charging zones (e.g., determining whether the user is traveling in California or Oregon). At finer levels of detail, the pricing schemes seek to distinguish between different road classes (e.g., to vary truck tolls based on highway versus nonhighway use), between specific links in the road network (e.g., to layer on additional fees for traveling on pre-existing toll facilities), or even between different lanes on a given link [e.g., for the hypothetical implementation of virtual high-occupancy toll (HOT) lanes]. Fourth, some of the projects also include the characteristics of the vehicle in determining fee levels. The most common examples of this fee structure include weight and axle configuration (for trucks) and vehicle emissions categories (to provide incentive for purchasing cleaner and more efficient vehicles).

The final major consideration in the area of policy and pricing pertained to the distribution of revenues. For most of the projects evaluated, the majority of the funds are dedicated to road maintenance and expansion. In several cases, however, a considerable portion of the revenue has been set aside to subsidize alternate modes such as transit or rail freight.

The in-vehicle equipment used within the various projects studied incorporates a wide array of technologies. In all cases, the equipment includes an on-board unit (OBU), essentially a computer that serves to integrate the other components, store data, and calculate charges owed. In addition, each configuration relies on one or more technologies to determine vehicle location or distance traveled, or both. Here, the range of possible options includes dedicated short-range communications (DSRC) devices, GPS receivers, geographic information systems (GIS) loaded with digital jurisdiction or road network maps (or both), odometer feeds, and dead-reckoning systems. Finally, each design also must include a means of transferring billing data to the collection agency. The three primary technology

choices for this component include DSRC, global system for mobile (GSM) communications (satellite-based cellular), and removable smart cards.

Collectively, the set of technologies incorporated within the OBU must facilitate four important functions: (1) measuring usage to determine fees owed; (2) communicating usage and billing information; (3) maintaining user privacy for passenger vehicles (this is less relevant for commercial trucks); and (4) preventing toll evasion.

To meter road usage, several different technology configurations have been proposed, studied, or employed:

• DSRC communicating with readers along the roadway: This is typically applicable for weight-distance truck tolls that apply only on highway links, where it is relatively easy and cost-effective to mount transponders on overhead gantries. Given the impracticality of installing DSRC transponders throughout the entire road system, this option has not been proposed for full, networkwide pricing schemes.

• Odometer with DSRC on/off toggle: In this option, DSRC transponders are mounted at the entrances to a jurisdiction (e.g., where a highway crosses from one country to another). When a vehicle enters a charging jurisdiction, the DSRC signal sets the on-board unit status to “on.” From that point, the odometer is used to measure distance traveled within the jurisdiction. When the vehicle exits once again, another signal from the DSRC transponder sets the on-board unit back into the “off” status.

• Odometer with GPS on/off toggle: This is similar to the DSRC toggle option. Instead of relying on transponders mounted at border crossings, however, the on-board unit relies upon a GPS signal (combined with a digital jurisdiction boundary map) to determine whether the vehicle is within a particular charging zone or not.

• GPS standalone:In this case, the GPS is used to determine both position and distance traveled. Unfortunately, the GPS signal may at times be lost temporarily (especially in urban or mountainous regions), making this approach impractical for full-scale implementation.

• GPS with odometer backup: To account for periods when the GPS signal is not available, the odometer can be used as a backup measure for distance traveled until the signal is available once again. Regrettably, the odometer is not capable of providing location information, making it difficult to determine whether the vehicle has remained within the same charging zone.

• GPS with odometer and dead-reckoning backup: To help determine location (and thus applicable charging zone) while a GPS signal is down, the unit also can be equipped with dead-reckoning equipment in addition to the odometer feed.

As noted, there are three primary approaches for communicating usage and billing data:

• GSM: This is the most costly option but also the most flexible. Because it allows for real-time communication from anywhere within the network, it also can be used to facilitate value-added capabilities such as way-finding, fleet management, and emergency distress signals.

• DSRC: Although this technology is robust, well tested, and inexpensive, it can be used only for communicating at fixed points throughout the network (specifically, where transponders have been mounted, such as on overhead gantries or at fueling stations). Though adequate for many applications, it does not provide the opportunity for value-added services, as does GSM.

• Smart cards: These are essentially small data-carrying devices that can be removed from the OBU and inserted into card readers (for example, at gas stations or on a home computer) to send billing data to the collections authority. With this option, the end user has full control in determining when the data are transferred; on the other hand, smart cards do not facilitate a fully automated billing process because some manual intervention is required.

Most of the systems studied devoted considerable attention to protecting user privacy. The primary concern has been to ensure that governments do not have unrestricted access to detailed travel records for individual drivers (this has been more of a concern for private passenger vehicles than for commercial trucking operations). To achieve this aim, two primary approaches have been proposed:

• On-board aggregation: The first approach, which is more prevalent for full-scale operational proposals, is to aggregate all travel information and determine the total bill owed on the on-board unit itself. With this strategy, the government never sees any of the details of the travel history for any individual, just the total amount of the bill.

• Third-party privacy agreements: In this second approach, the on-board unit communicates detailed travel information to a third-party billing agent, which in turn aggregates the data and submits only the total bill to the government. As with phone companies, the third party is legally obligated to keep these data private except in the case of a court subpoena. Consumers appear to be more wary of this approach, however, and to date it has been employed only within truck tolling projects or in research trial projects.

To help prevent toll evasion, two potentially complementary strategies have been discussed:

• Tamper-proof OBUs: Here the goal is to ensure that users are unable to turn off or temporarily disable the on-board units during periods of travel. Some of the alternatives suggested include tamper-proof seals on the OBU itself, disabling the engine if the OBU is not functional, and checking the OBU against the odometer to ensure that the mileage records are consistent.

• External verification: Under this strategy, DSRC transponders are mounted at various locations throughout the network, sending signals to passing cars to ensure that the on-board equipment is activated and functioning properly.

In reviewing the case studies, two major institutional issues of importance were identified. First, is the system designed to handle a single jurisdiction or multiple jurisdictions? Second, what are the respective public and private roles for oversight, operations, and the provision of technology?

About two-thirds of the case studies identified, including all of the weight-distance truck tolls and several of the distance-based user fee proposals, were designed, at least initially, to be implemented for single jurisdictions. Over the longer term, however, there appears to be a high probability that many single-jurisdiction programs will evolve to include multiple jurisdictions. For example, the distance-based user fee proposal in Oregon is currently structured to measure mileage within that state alone. However, if California or Washington elected to pursue a similar pricing scheme at some point in the future, then they might very well seek to leverage the same technology that Oregon already has developed. Fortunately, from a technical standpoint, it is relatively trivial to structure the on-board unit to record data and calculate fees for single or multiple jurisdictions. On the other hand, once peer-level jurisdictions (e.g., multiple states or countries) join together in a road pricing project, it may be necessary to develop new institutional capabilities for collecting the revenues and distributing the appropriate amounts to the different parties involved.

In terms of public and private roles, oversight responsibilities for most of the programs reviewed (with the exception of some of the distance-based insurance pricing studies) fell primarily within the public realm. For operations, in contrast, there was a roughly even split between public and private responsibility; most of the multiple-jurisdiction programs relied on private contractors for routine administration duties, whereas a larger percentage of the single-jurisdiction programs opted for public administration. Finally, all of the cases studies tapped the private sector for the provision of the on-board equipment and supporting technology. In most of the cases, especially those for which user participation is mandatory, single firms (or consortia) were contracted to be the sole providers of the technology.

However, for a few of the intended applications in which participation would be optional, the proposals have been structured to allow multiple vendors to compete for users on the basis of price as well as additional value-added services (such as navigational aids or fleet management).

Two principal implementation issues were identified: whether user participation is required or optional and whether the rollout is immediate or phased in over time. For most of the user fee programs, participation is mandatory, particularly for “internal” users (i.e., those who live or work within the charging jurisdiction). In contrast, participation is usually optional for travel monitoring (as opposed to pricing) programs (as in the case of the Australian “Austroads” program), variabilized insurance pricing, or “external” users (e.g., foreign truckers operating within a country with weight-distance truck tolls).

The mandatory participation programs must determine in advance whether the equipment rollout will be staged simultaneously or phased in over time (for optional programs, in contrast, the rollout is phased in by definition). Most of the weight-distance truck tolls, for example, have opted to require internal users to install the on-board equipment at the onset of the charging program. In contrast, most of the distance-based user fees that involve private passenger vehicles have envisioned some strategy for phasing in the equipment over time (for instance, with the purchase of new vehicles). It is important to note that for programs in which the rollout occurs gradually, it is necessary to develop a strategy for operating multiple charging schemes in parallel throughout the transition phase (for example, newer cars with on-board equipment installed might pay mileage-based fees while older cars continued to pay the fuels tax).

In reviewing the various factors that influence the prospects for political and public acceptance of new pricing schemes, two issues stood out most prominently: equity concerns and privacy concerns. With respect to equity, proposals for new pricing mechanisms invariably are subjected to higher levels of scrutiny than existing transportation finance programs. For example, equity concerns rarely are raised over the increasingly common dedication of sales taxes, despite the fact that such taxes are recognized widely to be regressive with respect to both income and highway system use. On the other hand, equity concerns almost always loom large for electronic tolling proposals, especially congestion tolls. This likely is due to the fact that they usually represent a “new” form of pricing (as opposed to a distance fee, which essentially would replace the existing gas tax), and because they place the

correlation between ability to pay and benefits received into especially sharp relief. For the various projects that incorporated some form of congestion tolling, we observed the following:

• Equity concerns have contributed to the demise of many congestion pricing proposals.

• Actual equity outcomes can vary considerably from one project to the next, depending on user demographics and program design.

• Despite frequent equity concerns, congestion tolling is on the rise.

• Many congestion tolling programs have mitigated equity concerns through the dedication of revenues (for instance, to subsidize transit).

In contrast to congestion toll proposals, equity issues are not usually raised with regard to weight-distance truck tolls, distance-based user fees, or variabilized insurance.

As with the question of equity, the level of concern over privacy issues depends on the nature of the pricing program. Generally speaking, privacy issues are less relevant for weight-distance truck tolls, given their commercial nature, or for congestion tolls, which don’t typically track vehicles continuously through time and space. In contrast, privacy can be perceived as a significant issue for general-purpose distance-based user fees, as such programs involve private citizens and use equipment that, at least theoretically, allows for extensive vehicle tracking and monitoring. From the review of the various case studies, the following observations were made:

• Privacy concerns do not appear to pose legal issues.

• Public concern over privacy issues may not in fact be particularly widespread, given the prevalence of credit cards and cell phones, two other devices that provide a wealth of detailed information about individual behavior.

• Where privacy is a significant concern, it has been addressed at the technical level (through on-board aggregation of data) or at the programmatic level (with third-party billing and confidentiality agreements).

In addition to equity and privacy concerns, several other factors that may play a strong role in the level of public and political acceptance of new pricing schemes were identified. These include the following:

• Severity of the problem and effectiveness of the solution: New pricing schemes appear more likely to be accepted if the problem is considered severe, if other solution strategies have already failed, and if the proposed pricing scheme is deemed likely (or has been demonstrated elsewhere) to be effective.

• Integration with complementary policies: New road pricing schemes that integrate complementary policies—such as the improvement of transit options—appear to have increased the likelihood of implementation.

• Size and scope of the project: Projects of larger size and scope—with more users affected and more aspects of road use priced—appear to face more difficult prospects for political success given that they may engender resistance from a larger and more diverse array of stakeholders.

• Dedication of revenues: From the cases reviewed, it appears that the public is more willing to accept pricing programs when revenues are dedicated to transportation improvement projects rather than allocated into general funds.

• Manner in which stakeholders are compensated: In most of the programs investigated, one or more stakeholder groups will be affected adversely by the new pricing scheme. To counter or mitigate potential political resistance, many of the successful programs developed some way to compensate such groups. For instance, the weight-distance user fee in Switzerland raised the overall level of user fees for truckers (so as to encourage mode shift to rail) but also allowed for higher weight limits on the highway network in order to facilitate greater operating efficiencies among trucking firms.

• Degree of choice offered, or precluded, by the program: Findings show that programs seeking to expand the choices available to travelers (such as HOT lanes or cordon congestion tolls integrated with improved transit facilities) have tended to enjoy greater prospects for success than programs that limit or preclude the level of choice (such as all-lanes congestion tolls or cordon toll proposals in cities not well served by transit).

• Transparency and user-friendliness of the system: Developing fare structures that are readily understood and payment collection technologies that are seamless from the user’s perspective appears, from the case studies reviewed, to be critical to establishing a high level of public and political acceptance.

• Effectiveness of the enforcement strategy: In many of the case studies reviewed, the effectiveness of the enforcement strategy was cited as a major issue for public acceptance; more specifically, users appear more likely to resent a new pricing scheme if they perceive that others may be able to cheat the system and evade payment.

Of the many types of issues involved in our case studies of electronic tolling, three appear to exert the greatest influence on the prospects for the success of distance-based user fees: (1) the embedded policy objectives, (2) the technical strategy, and

(3) the factors that influence political and public acceptance. Institutional and technical implementation issues are also important, of course, but these details appear less likely to affect the technical and political feasibility of electronically based pricing programs.

With respect to policy objectives, distance-based user fees can be designed to accomplish a wide array of goals, depending on the characteristics of travel that are metered or priced.

• Revenue enhancement or preservation: A distance-based user fee can readily serve as a replacement to the standard fuels tax, and its effectiveness would not be compromised by increasing vehicle fuel efficiency (or even the introduction of alternative-fuel vehicles) in the years ahead. Given the substantial price tags associated with transitioning to these types of systems, however, it is not clear whether this approach would be superior to simply increasing current fuels taxes over the short term (though, as noted above, such increases face increasingly difficult political odds). Conversely, a distance-based user fee may very well prove necessary within several decades with the anticipated widespread introduction of alternative-fuel vehicles.

• Optimizing road capacity, managing demand: By using the technology base for a distance-based user fee system, it is relatively straightforward (from a technical standpoint) to layer on congestion tolls that would apply along specific corridors or within crowded urban areas during periods of peak travel for the purposes of optimizing road capacity or managing demand and encouraging mode shift.

• Reducing road damage, improving the environment: It is also possible to build in offsets to the standard distance fee based on axle weight or emissions class in order to encourage users to purchase and operate vehicles that impose less damage on roadways or the environment.

On the technology front, the most significant finding is that it is technically feasible and increasingly cost-effective to develop a system for distance-based user fees. In terms of specific technologies and general technical strategies:

• GPS: GPS by itself is not sufficiently reliable to measure location and distance traveled, given that the signal often may go down during travel between tall buildings or in mountainous areas. For this reason, such systems need to be supplemented by an odometer feed (as a backup for distance traveled) and possibly a dead-reckoning system (as a backup for location). The question of accuracy may be another important issue. For applications where it is necessary only to determine whether or not a vehicle is within a particular jurisdiction (e.g., a country or a state), GPS and existing digital maps provide a sufficient level of accuracy. However, for applications in which

it is necessary to distinguish between different road links on the network, differential GPS signal correction and highly accurate (and expensive-to-create) road network maps will be required.

• Communications strategies: DSRC, GSM, and smart cards all represent viable communications options; the appropriate choice depends on price (GSM is the most expensive by far) as well as desired functionality (GSM is also the most flexible).

• Enforcement strategies: To prevent toll evasion, tamper-proof OBU strategies appear to offer the most promise, though external roadside checks using DSRC transponders may add a useful level of redundancy.

• Simple system designs: Generally speaking, and not surprisingly, applications that have relied on relatively simple technical configurations (leveraging, as often as possible, off-the-shelf technologies) have experienced the greatest implementation and budgetary success. Increasingly, electronic tolling programs are starting with simple systems that are upgraded to a greater level of complexity later.

• Conservative implementation schedules: For many projects, the process of development, integration, and planning has taken far longer than originally anticipated. This underscores the importance of providing sufficient flexibility within the implementation timelines to account for unanticipated technical difficulties.

• Backup plans: As a corollary to the above, program designers (in most, though not all, cases studied) have designed system redundancy and backup plans for levying user fees should technical difficulties lead to delays in the implementation of the electronic tolling system.

Finally, in terms of the factors that influence the prospects for political and public acceptance of distance-based user fees, the following issues are the most relevant:

• Equity concerns: In general, equity is raised as a concern more for congestion tolls than for distance-based charging schemes. In distance-based user fee proposals not involving congestion surcharges, equity concerns have been far less of a political barrier. But since one of the ultimate goals of many distance-based electronic tolling programs is to develop systems that eventually include both distance fees and congestion tolls, equity concerns may be raised subsequently for already established tolling programs.

• Privacy concerns: In contrast to equity, concerns over privacy are most common in distance-based user fee programs, given that the combination of technologies employed within on-board equipment can be used to record and disseminate detailed information on the travel patterns of individual

drivers. Fortunately, it is possible to ensure the privacy of user data, both at the technical and institutional levels. On the other hand, many press accounts continue to highlight concerns over privacy, despite the fact that this issue has been addressed satisfactorily in many of the cases studied. For this reason, efforts to implement distance-based charging schemes often include coordinated public education campaigns to address and diffuse popular and political objections to tolling proposals on privacy grounds.

• Other factors influencing public and political acceptance: Along with equity and privacy, a number of other issues appear to be important with respect to building public and political support for new pricing programs such as distance-based user fees. Most notably, these include the severity of the problem to be addressed and the inadequacy of other solution strategies, the degree of integration with other related policies (such as the provision of improved transit service), the degree to which “losers” under the new pricing regime can be compensated in some manner, perceptions over the adequacy of the proposed enforcement scheme, and the expansion or contraction of travel options created by the program.

• Keys to building public and political support: In addition to the programmatic factors that can influence the level of public and political acceptance, experience from the various cases studied indicates that there are a variety of strategies that pricing program proponents have pursued to enhance the prospects for political success. These include establishing the technical details of the program early on (so as to build confidence in the feasibility of the project), engaging in sophisticated marketing efforts (including focus groups, targeted messaging, and coordinated framing of the debate), reaching out to key stakeholder groups early in the process, cultivating political champions, actively courting the media, and providing positive testimonials from other successful projects of a similar nature.