Executive Summary

Zürich is famous for the quality of its public transit system. Zürich's transit system is an attractive way to move about the city. The system is easy to use, fast, frequent, reliable, and inexpensive. Zürich's well-functioning transit system makes a significant contribution to the city's overall high quality of life.

Critical to Zürich's success is a comprehensive "transit priority" program implemented over the last 30 years. Transit priority improvement techniques are designed to speed up transit. According to Professor Robert Cervero, "The results of this program have been nothing short of exceptional. Zürich has one of the highest rates of transit usage today, about five hundred sixty transit trips per resident per year, almost twice as many as Europe's largest cities."See Priority transit vehicles require new traffic regulations and roadway changes on all city routes.

The most important quality of Zürich's public transit system is that it functions as a network. It is fast, easy, and comfortable to get from point A to point B in the city or region. Public transit is easy at almost any time of day and any day of the year. While many trips require transfers, this is no problem because all the lines in the network work well. The transit priority program is a fundamental reason why this is true.

The transit priority program enabled all of Zürich's surface transit lines to improve more quickly and for less money than constructing a new underground rail line. Consequently, the entire transit network could be improved rather than just building a single line. This was the choice that Zürich faced in a 1973 election that asked voters to spend 1.2 billion Swiss Francs (SFr) for construction of a new underground transit system. Voters rejected that measure and voted instead to provide 200 million SFr over 10 years to implement transit priority measures to make the existing surface transit system more efficient.

Improving a surface transit system that can operate with transit priority has many advantages over an underground system. A surface line can have more accessibility and does not require people to go underground to access the system. A surface system is simple to operate and is designed to fit well into the urban environment. The natural trade-off is less space for automobiles. However, Zürich's economic success and high livability prove that this does not need to be a problem. It is still possible to drive in Zürich, but public transit is so good that driving is not necessary for most trips.

The objective of this research was to describe transit priority techniques in Zürich and understand how the city implemented its program. Most transit priority improvements are relatively simple and inexpensive; however, they have proved to be difficult to implement and sustain. The research effort consisted of a case study with interviews and surveys. We interviewed many persons associated with the development and implementation of Zürich's transit priority program. A survey to evaluate support of transportation decision-makers in Santa Clara County, California, illustrated transit improvements in a typical U.S. city. The data was compared to a similar survey in Zürich. The findings help us to understand how elected officials think about transit improvements.

This report summarizes the case study findings and the Santa Clara County survey. The report targets cities and transit agencies interested in implementing transit priority techniques, specifically those considering low-cost ways to improve transit service quickly and efficiently.

WHY IS TRANSIT PRIORITY IMPORTANT?

Transit priority is important, extremely cost effective, and a way to improve transit service. Transit priority improvements advance customer service by providing faster and more reliable service. Improvements empower transit's bottom line by enabling it to operate more service with the same resources and by attracting more passengers. By reducing conflicts with private traffic, transit priority improvements also can reduce accidents and driver stress.

Transit priority is especially relevant because the vast majority of transit service today shares right of way with other traffic. Whether buses or light rail systems, operating transit in mixed traffic leads to delays and unreliable service. Unfortunately, transit priority improvements are neglected. Improvements could address these problems in favor of larger projects such as new rail transit systems.

Transit Priority Improvements: A Feasible Transit Investment

While rail transit clearly provides an attractive and environmentally friendly transit system, it is feasible only in major corridors where high ridership justifies the large capital investment. Furthermore, it is difficult to find funding for these expensive projects. In contrast, in the cost-benefit analysis, transit priority improvements are less expensive and easily justified. Therefore, transit priority improvements represent a significant opportunity for improving transit service in many U.S. cities.See Vuchic, Vukan, et. al. The Bus Transit System: Its Underutilized Potential. U.S. Department of Transportation, Federal Transit Administration, May 1994, 1.

Transit priority improvements enhance the overall effectiveness of the transit network in cases where large capital investments are justified. For example, implementing a comprehensive transit preferential program on feeder services for a new rail line can create a transit network that maximizes the major capital investment's effectiveness.

Finally, transit priority improvements can build transit demand to a level that will support construction of more significant investments, such as a light rail lines, in the future. In these cases, the initial transit priority improvements can often be enhanced for the new service (for example, constructing a light rail line in a bus facility, as is being done in Seattle).

Today, many cities have growing traffic congestion and are trying to rebuild their transit networks. They have two main choices: build an entirely new transit network or line, an expensive and long process, or focus on making the existing network work better by implementing transit priority techniques. Zürich took the second approach, a relatively unique choice in an era of major transit capital projects, and created one of the world's best transit systems.

Types of TRANSIT PRIORITY IMPROVEMENTS

Transit priority improvements are generally defined as a "range of techniques designed to speed up public transit vehicles and improve the transit system's efficiency." They include physical improvements, operating changes, and regulatory changes. They are often relatively low-cost ways designed to reduce transit vehicle delays.

For purposes of this research, a relatively broad definition of transit priority techniques was adopted in order to consider improvements that can significantly benefit from simultaneous implementation of transit preferential techniques. The best example is a transit mall, which some might not define as a transit priority improvement. However, transit malls are clearly most effective when implemented with transit system operations improvements such as coordinated scheduling and proof of payment, and therefore they are included in this analysis.

This research categorizes transit priority improvements into the following four types:

Roadway Improvements/Traffic Regulations -- Minor changes to roadways, relocation or reduction in the number of transit stops, and traffic regulations designed to reduce transit vehicle delays.

Traffic Signal Priority -- Traffic signals that reduce delays to transit vehicles by providing them with green lights when they approach.

Transit System Operations -- Changes to operation of the public transit system designed to reduce delays, including low-floor buses, proof of payment, and system control centers.

Separate Right of Way -- Sections of roadway designated for the exclusive use of transit vehicles, allowing transit to bypass congestion. For purposes of this research, two special cases are included under the separate right of way category: transit malls and major capital investments.

As this list indicates, there are many types of transit priority techniques. The next chapter describes each of these general categories in more detail.

IMPLEMENTATION OF TRANSIT PRIORITY TECHNIQUES

The effectiveness of a transit priority program depends on implementation. Implementation of transit priority improvements can be categorized in the following four levels:

Limited Implementation -- Transit priority techniques are implemented individually in various locations in the transit network (for example, individual roadway improvements).

Route Level Implementation -- Transit priority techniques along the entire route (for example, building exclusive transit lanes).

Areawide Implementation -- Transit priority improvements are implemented in a particular area (for example, transit malls).

Comprehensive Implementation -- Transit priority improvements are implemented to all transit routes and changes made to the way the whole system operates (for example, proof-of-payment fare collection).

The best way to implement a transit priority program is to implement it throughout the network, as Zürich has done over the past 30 years. This type of program would evaluate each aspect of transit operation systematically and seek ways to speed up the service to make it more attractive to customers and more efficient to operate. It would perform this analysis on the entire transit network.

In this context, it is interesting to consider the overall operation of many transit systems today. Typically, they are similar to the horse-drawn omnibuses that first provided transit services. Transit vehicles still stop at almost every corner, fares are collected, and transit vehicles share the road with other vehicles. However, the number of other vehicles has grown astronomically, and operating procedures have not taken significant advantage of new technology such as automatic vehicle location.See Ibid., 2.

Difficulty in Implementing Transit Priority Improvements

Many cities, including Zürich, implemented transit priority improvements in the early 1970s. While Zürich continued to expand its program over the last 30 years, many U.S. cities have neglected and not expanded their transit priority programs. Examples of neglect include lack of enforcement, opening bus lanes to other traffic, and reduced interest in implementation of new programs.See Ibid., 2.

Implementing transit priority techniques is difficult because providing priority for transit can mean taking capacity from other roadway users. The difficulty in implementing transit priority improvements is ironic, because most transit priority techniques are relatively simple and inexpensive. Essential transit priority implementation difficulties include:

Low technical competence and lack of expertise on transit priority techniques and implementation

Lack of support or direct opposition by different agencies or departments

Difficulties of coordination between agencies and departments

Pressures by automobile users

Poor public understanding of the benefits of transit priority

Opposition to changes by businesses and residents.

The difficulty of overcoming these obstacles led to skepticism and a defeatist attitude in transit agencies and planning departments about implementing transit priority improvements.See Ibid., 29.

The support of elected officials is an essential requirement to defeat obstacles and implement a transit priority program. A 1973 citizen's initiative to improve operations of the existing surface transit network sparked transit support in Zürich. The general initiative provided funding and political support for implementing transit priority improvements. Elected officials became supportive of the transit priority program after passage of the initiative. The chapter See History: Zürich's Transit Priority Program presents a brief background on the citizen's initiative and its history.

In terms of elected official support, an especially interesting survey was done for the City of Zürich in 1993, comparing people's opinions of the degree to which transit should have priority to elected officials' perceptions of what the people thought.See Socialdata GmbH, Munichen; Bauamt I der Stadt Zürich. Mobilitat in Zürich -- Verhalten. 1993. This survey showed that elected officials significantly underestimated the degree to which their constituents supported transit priority. A similar survey done in Santa Clara County for this research project shows elected officials there also may underestimate the degree of public support for transit improvements.

In both surveys, constituents substantially prefer roadway solutions, although the elected officials themselves said that they supported transit solutions. The survey respondents believed that voters support mass transit primarily to get others off the road and therefore campaigns must emphasize transit's impact on traffic congestion. The fact that public officials seem to underestimate public support for transit improvements is troubling for the transit industry. Strong public official support is needed to implement complicated transit improvement projects. See Public Support for Transit Improvements describes the Santa Clara County survey.

In summary, most transit priority techniques provide clear, significant benefits to transit systems. The past and future problem is always how to get them implemented. One of the main objectives of this research is to learn how Zürich was able to implement its comprehensive transit priority program.

TRANSIT PRIORITY IN Zürich

Zürich implemented all four types of transit priority improvements throughout its network, specifically:

Priority transit vehicles require new traffic regulations and roadway changes on all city routes.

Zürich designed and built a unique citywide traffic signal prioritization system that provides transit priority without affecting other traffic. This extremely sophisticated system also controls traffic volumes in the city to prevent gridlock and improve livability.

Zürich adopted system operating techniques such as proof-of-payment and has constructed a high-tech systems operations center to maintain schedule reliability and service quality.

Much of Zürich's transit system operates on exclusive right of way constructed by redistributing road space from mixed traffic to transit only. In some cases, creative traffic signals provide transit priority when there is not enough room for exclusive lanes. The Bahnhofstrasse, Zürich's main downtown street, is a transit mall with some of the highest rents and most elegant shopping in the world.

The city implemented improvements designed to reduce the amount of through traffic and reduce traffic speeds in neighborhoods as part of a comprehensive program designed to improve both transit priority and livability.

Commuter Railroad Network

A canton is approximately the geographical and population equivalent of a U.S. county but the political equivalent of a U.S. state. In addition to Zürich's transit service, the Canton of Zürich led the effort to build a regional commuter railroad network (S-Bahn or fast train) in the 1980s. As part of the S-Bahn project, the Canton formed the Züricher Verkersverbund (ZVV), a regional agency responsible for coordinating fares and schedules of 42 different transit operators.

Efficiency and quality of service heightened the city's public interest in the transit system. Zürich's regional transit system directly feeds the city's tram and bus system. The city continued dedicating roadway space for transit and to reduce parking. Zürich developed a two-level transit system to serve the transportation needs of a major urban region. Zürich improved the efficiency and speed of the surface transit network by comprehensively implementing transit priority throughout the city network, increasing the number of stations located within the city on the regional S-Bahn system.

Consequently, the tram and bus networks provide shorter intermediate-length trips. Longer intermediate-length trips will be made on the S-Bahn network, alleviating the need for an intermediate, third-level system (that is, a subway or Metro system). See Zürich's Transit Priority Program describes Zürich's major types of transit priority implementations. See Complementary Transportation Programs outlines the complementary measures used, including traffic calming, the S-Bahn, and transit system coordination.

Implementation Lessons from Zürich

Important and overarching lessons can be learned from Zürich. Primary ingredients for success are continuing public support, effective political leadership, and motivated city employees. Successfully implementing a transit priority program means taking a comprehensive, long-term approach to improving the transit system.

Lessons from Zürich are transferable to other cities. First, Zürich shares many of the same problems facing other modern cities. Jobs and housing are decentralizing from the center, automobile ownership and traffic congestion are increasing, and employment is shifting out of traditional industries to service and professional sectors. Zürich's elected leaders face the same pressure as politicians in other cities, including reducing taxes and improving livability. Finally, the reliance on local funding (taxes) for capital improvements and the importance of the initiative process in capital improvement decision-making are becoming more common in the rest of the world.

Zürich started with a big advantage over other cities -- had a well-used and highly respected transit system. Zürich simply needed to upgrade, by incrementally adding transit priority improvements. Cities with less-developed transit systems might not achieve the same quick results. Zürich's approach remains an excellent model.

Many lessons presented below are not surprising but common sense, for example, obtain and maintain strong public support. In these cases is not so much the lesson, but rather the specific techniques and strategies that Zürich used to attain these conditions. See Implementation Lessons from Zürich describes these lessons and strategies in more detail.

Lesson #1 : Obtain and Maintain Strong Public Support

Public support is the most critical element of implementing any government program. Public support is particularly important for a transit priority program. Effective transit priority programs create winners (public transit) and losers (other roadway users). A particularly problematic aspect of transit priority programs is that they are most effective when implemented comprehensively so it takes some time before they can generate public support, but the specific improvements generate immediate criticism from other roadway users. In Zürich, the public took an active role in forcing the city administration to implement transit priorities more comprehensively and more boldly than would have been possible without strong public support.

A group of citizens put forward the concept of implementing transit priority improvements throughout Zürich's existing surface transit system as an alternative to constructing a major new rail transit line. Passage of their transit priority initiative provided funding and a degree of political support for program implementation. Thirty years later, it is obvious that their plan was better from the perspective of transportation and urban livability as well as being significantly less expensive than the proposed rail system.

Persistent activists forced the city leaders to implement the transit priority improvements to a higher degree than they might have otherwise. Transit priority improvements can be implemented by degree, and strong implementation is better for transit but has more impacts on private vehicles. Without continuing support for transit priority from activists, it would have been difficult to overcome the objectives of private vehicle drivers. Activists placed pressure by lobbying, multiple initiative campaigns, and political endorsements.

The Zürich lesson clearly shows that public support is required to implement a transit priority program and less active support is required as evidence of system benefits become convincing. The program provides a winning solution for all by following those lessons.

Lesson #2 : Enlist Elected Official Support

The public support of elected officials is required to implement a transit priority program. Elected officials force government departments (often overwhelmed with their day-to-day responsibilities) to undertake long-term and challenging citywide programs.

In Zürich, elected official support was slow in coming. Almost all officials supported construction of the heavy rail transit system over comprehensive implementation of the transit priority program. They did not want to implement the more controversial parts of the transit priority program. Slowly, after years of active pressure from citizens groups and as they began to see the benefits of a comprehensive transit priority program, elected officials began to support the program. It is still difficult to implement improvements to the optimum degree, but elected officials in the city of Zürich are generally on-board with the program.

Obtaining elected official support is not always easy. Based on surveys in Zürich and in Santa Clara County, elected officials often underestimate the depth of support for transit among the voters and are too timid in their support for transit priority techniques.

Lesson #3 : Use Smart Implementation Techniques

Outside advocates are needed to force government to take action. However, to maintain and sustain public support, government officials must implement intelligent programs. In Zürich, city planners used several techniques to foster public support for the transit priority program, including:

Implement high-impact projects quickly and publicize their benefits -- In Zürich, high-impact projects were quickly implemented and their benefits were well publicized. A lesson from Zürich is that having good projects on the shelf and ready for implementation was helpful to the program.

Don't unnecessarily alienate people -- There are cases where transit priority improvements impact private transportation, but the lesson from Zürich is to only do this where it is really necessary and try to minimize the impacts. For example, Zürich designed its traffic signal priority program to provide the minimum amount of time necessary for transit priority. This enabled the system to provide extremely effective transit priority without hurting traffic circulation.

Implement transit priority techniques together with improvements that increase neighborhood livability -- In Zürich, transit priority improvements were implemented as part of a larger and more comprehensive program designed to improve city livability. As a result, Zürich sped up transit and improved neighborhoods. Examples include building bus stops that are pleasant pedestrian spaces and introducing turn restrictions that reduce delays to transit vehicles and eliminate through traffic in neighborhoods.

The lesson from Zürich is that smart implementation helped provide public support for the transit priority program and minimize criticism.

Lesson #4: Organize Government to Effectively Deliver Program

Transit priority improvements by their nature affect many different departments, and frequently, bureaucratic concerns prevent them from being implemented effectively. Zürich addressed the issues by creating the following task forces:

Executive Council -- A group of elected officials and city department heads that direct city departments to develop transit priority improvements and provide the political support for implementing them.

Working Party -- A group of department heads and planners from several departments who collaborate on the development of specific transit priority improvements. An interesting aspect of the Working Party is that as a group with changing representation, many members of city departments have participated on it at one time or another. This has provided many staff members with an understanding of transit priority techniques that they use in their other projects.

While departments work together on developing projects, the Traffic Police has the sole responsibility for making changes to the roadway system, including signs, traffic signals, painted markings, and road construction. This allows changes to be made quickly and efficiently, once a plan has been adopted.

Lesson #5 : Careful Traffic Engineering and Technology Is Critical

One argument against complex programs such as transit priority is technology. People often say that something cannot be done. This was also true in Zürich. Government officials said that certain programs could work in smaller, less complex situations but not in a large system with a great deal of private traffic like Zürich. Once Zürich voters approved the transit priority initiative, the city was forced to implement the program. Difficult technical solutions were developed; it was not easy, but it was done.

Two main points regarding Zürich's technology development and applications are as follows:

Technology Application -- Careful Traffic Engineering -- The lesson from Zürich is that sophisticated traffic engineering helps reduce opposition to transit priority techniques. Providing transit priority often means taking street space that has been used for mixed traffic and dedicating it to transit. This requires creating new routes for private vehicles. In Zürich, sophisticated traffic engineering techniques such as channelization and traffic signal placement enable private vehicles to circulate while still providing transit with priority. Many of Zürich's main transit stops serving seven or eight transit routes are in squares shared with private vehicles. However, these squares are carefully designed to ensure transit is the priority and private vehicles efficiently travel through the square.

Technology Development -- Traffic Signal System -- Existing traffic signal technologies could not achieve the desired degree of transit priority. One advantage Zürich had in taking a fresh perspective is that staff members were operational research specialists, not traffic engineers. Staff members took a systems approach to transit priority and worked closely with other departments to understand the problems. Staff members learned to drive buses and trams to research what drivers could and could not do. City engineers took a fresh look at the problem and developed their own technology. Today, the system successfully provides transit priority throughout the city as well as improving vehicle traffic flow.

In combination, thinking carefully about applications of transit priority techniques, addressing technical implementation issues, and creating new technologies solve problems. However, all are fundamental requirements to programmatic success.

Lesson #6 : Implement Complementary Programs to Improve the Transit System

Transit priority alone will not create an excellent transit system. Basic requirements are safety, good service, and efficiency. The transit system itself has to provide good service in terms of frequency and customer attractiveness, for example, safety. In addition to this basic transit service, there are several complementary programs that cities can implement to further support and improve the transit system. In Zürich the following complementary programs were implemented:

Plan Land Uses to Support Transit -- Zürich worked aggressively to encourage land uses that support transit, both through conventional land use planning techniques such as increasing density with zoning and development agreements, and by making the areas best served by transit attractive places to live, work, and visit. Initial efforts focused on improving center city urbanity by reducing parking and traffic and then using the freed-up space to speed up transit, create pedestrian zones, provide space for public events, and create a lively and entertaining downtown. This helped business, and now the program is being applied to redeveloping areas and new development.

Reduce Traffic Volumes -- Zürich has a relatively long history of developing measures designed to actively restrain and reduce private motor traffic in the city. Zürich has used three main approaches to control the vehicle traffic in the city: traffic calming, reduction of roadway capacity, and parking controls. As with other programs, Zürich has taken a comprehensive and thoughtful approach to controlling vehicle traffic. While activists would argue that there is still too much traffic in the city, the government would say that there is less than there would be without these programs.

Regional Transit Coordination and System -- The Canton of Zürich organized the Züricher Verkehrsverbund (ZVV) to coordinate fares and schedules of the region's 42 different transit operators. Today, careful scheduling links systems and makes it possible to use a single ticket. The canton also built a regional fast suburban rail system (S-Bahn) that provides regional mobility and serves as the basis for schedule coordination. Good regional transit has increased ridership on Zürich's city transit system and provides an argument for reducing traffic volumes on major routes into the city.

These complementary programs have helped support Zürich's city transit system. Strong ridership and public approval exist for Zürich's transit system. Public approval is a strong argument to strengthen the transit priority program.

Lesson #7: Use Capital Investments to Leverage Institutional Change

One of the most interesting lessons identified in this research was how the Zürich region used the need for a large capital investment to bring about institutional change. As part of the project to construct the S-Bahn, the Canton of Zürich required that transit fares and schedules for all 42 different transit operators be coordinated. The canton only agreed to fund the major investment if a new agency was created to bring about regional coordination. The canton's funding provided the leverage necessary to get the different public and private transit operators to the table to develop a coordination system.

Lesson #8: Think Carefully at the Systems Level

An interesting aspect of Zürich is the region's adoption of a hybrid type of transit system. Zürich modified a two-level transit system. Surface streetcars and buses for local transit and high-speed commuter rail for regional transit provide a better match for Zürich's transportation needs. Nevertheless, the standard three-level system would have worked. A two-level system would not work for many larger cities.

There are significant cost savings and transit service benefits. The two-level system reduces transfers by carefully considering systems-level choices before choosing a planning approach for improving a transit system.

CONCLUSION

Zürich is one of the most livable cities in the world, and one reason is the high quality of its transit system. The transit system is efficient and extremely attractive to passengers. It is possible to travel easily and quickly throughout the city and region using transit.

Zürich created its excellent transit system by implementing a comprehensive transit priority program designed to speed up transit and increase its efficiency throughout the transit network. This low-cost approach was chosen over proposals for expensive new underground rail networks. The transit priority program has created a more appropriate transit system for Zürich and has cost significantly less than a new rail system. Other cities can learn a great deal from studying this approach and the transit priority techniques used in Zürich when considering how to improve their own transit systems.

Zürich transportation consultant Willi Hüsler put it best when he said, "Zürich is proof that a conventional tram and bus system, omnipresent in the most attractive streets and squares of the city and supported by a high-tech operation and control system, is an extraordinarily effective combination. A combination that is more cost effective than an underground system in a city like Zürich." See Husler, Willi. Zürich Tramway: Friend of the Environment. n.d., 61.

See Zürich's Transit Priority Program describes how Zürich implemented specific transit priority improvements. It includes examples of specific projects and describes the process of developing Zürich's citywide traffic signal control system.

See Complementary Transportation Programs outlines complementary improvements made to reduce traffic in the city and to improve the regional transit system that further supported Zürich's transit system. Transportation measures in Zürich's citywide transportation policy that have contributed to the success of the transit priority program include traffic calming and parking restrictions. A well-operating regional transit system has been critical to Zürich's success. As a result, people traveling to and from the sprawling city of Zürich can use transit rather than drive their cars into or out of the city.

See Public Support for Transit Improvements presents an analysis of public officials' perceptions on implementation of transit improvements in Santa Clara County, California. It also describes results of a survey that asked questions similar to a 1993 survey of elected officials in Zürich, and describes the similarities and differences between the groups in order to provide ideas for implementation of transit improvements in the United States.

See Implementation Lessons from Zürich summarizes lessons identified in this research that helped Zürich implement its transit priority program and presents a short description of why these lessons are relevant to other cities.

RESEARCH METHODOLOGY

This report presents results of an on-site case study in Zürich and a survey of transportation decision-makers in Santa Clara County, California. The Zürich research was carried out in the Fall of 1999 by Andrew Nash. It consisted of extensive, detailed interviews with individuals responsible for planning and operation of Zürich's public transit system. A list of individuals interviewed is contained in See Acknowledgements Many of those interviewed were active in the mid-1970s when Zürich adopted its transit priority program, and their insights were especially helpful.

The survey of transportation decision-makers in Santa Clara County, as well as most of the chapter describing it, was completed in the Spring of 2000 by Professor Ronald Sylvia and Dan Goodrich of San José State University. The survey team asked specific questions of more than 30 persons currently or formerly active in transportation planning in the county, mostly elected officials.

Transit Priority

Introduction

Transit priority improvements are generally defined as a range of techniques designed to speed up public transit service. They consist of physical improvements, operating changes, and regulatory changes designed to increase the speed of transit vehicles and improve the system's overall efficiency. By reducing conflicts with private traffic, transit priority improvements also can reduce accidents and driver stress.

Transit priority techniques are generally relatively low-cost improvements; however, specific techniques vary from small, simple street improvements in particular locations to introduction of major capital improvements and changes to the entire transit network.

There are two ways to characterize transit priority programs: in terms of the types of improvements and in terms of the degree of their implementation in the transit network. The following sections summarize four types of transit priority techniques defined for this research, implementation levels of transit priority techniques, and more detailed descriptions of each transit priority improvement category.

TRANSIT PRIORITY TECHNIQUES

There is significant literature that describes transit priority techniques. Two especially recommended sources are the City of Portland's Transit Preferential Streets Program Sourcebook and Program Report .See Expected delays to transit riders, motorists, pedestrians, and other users that are attributable to signal control decisions. The first document presents a description and guidelines for implementing a series of transit preferential techniques. The second document presents a report on the potential to implement specific techniques on five Portland transit corridors.

Roadway Improvement -- Traffic Regulations

The simplest category of transit priority improvements consists of changes to the roadway that improve the operation and speed of transit vehicles. Roadway changes are traffic regulations, minor physical improvements, and changes to transit stops. Specific examples include:

Parking Restrictions -- One main cause of delays to transit vehicles is waiting while private vehicles maneuver in and out of parking spaces. Parking restrictions and controls can be implemented to reduce the impact of parking movements on transit vehicles and to provide space needed for exclusive transit lanes.

Turn Restrictions -- Turning vehicles are another significant source of delay for transit vehicles. Implementing turn restrictions carefully can significantly reduce these delays.

Transit Exemption from Turning Requirements -- In some cases, restrictions to turning movements can lengthen and delay transit routes. In these cases, it can be beneficial to exempt transit from the turning movement restriction.

Loading Restrictions -- Historically, vehicle loading on public streets has been a problem in cities throughout history. In ancient Rome, goods delivery was banned during the day because of congestion. Careful design of loading areas can improve transit priority by reducing interference with transit vehicles.

Transit Stop Location -- The location of transit stops has a large impact on transit speed. Transit travel times can be improved significantly by relocating stops to places with better traffic conditions (for example, to the near or far side of an intersection, as appropriate). Eliminating or consolidating stops reduces travel time but at a cost to accessibility, so this must be carefully evaluated; however, many transit routes probably have more stops than really necessary.

Transit Boarding Islands -- Boarding islands enable transit vehicles to pick up passengers without moving into the curb lane. This keeps them in a moving travel lane and out of an intersection right turn lane -- especially critical where right-turning traffic is delayed by pedestrian crossings.

Curb Extensions -- Curb extensions at transit stops, known as bus bulbs, are similar to boarding islands in that they allow transit vehicles to pick up passengers without moving into the curb lane. However, they can interfere with right-turning vehicles when located on the near side of an intersection. Therefore, their location must be carefully planned to maximize their effectiveness.

The role of good traffic engineering in successful implementation of roadway improvements and traffic regulations cannot be overemphasized. Roadways serve many different types of users, and transit priority improvements should not penalize those other users. Sophisticated traffic engineering techniques must be used to accomplish transit priority and minimize the impact on other users. Transit planners must have good relationships with traffic engineers and be able to work cooperatively on improvement projects.

Traffic regulations and roadway changes often are controversial to drivers and adjoining property owners. Public support is critical to implementation of transit preferential programs. Roadway improvements must be designed to meet conditions in public areas and minimize unnecessary negative impacts.

Another effective method of attaining public support is to work with the community to design transit priority improvements as part of a comprehensive program designed to improve transit service and neighborhood livability. If a transit priority improvement can be designed to retain access to local businesses and creates a more pleasant pedestrian environment, it will be easier to implement than if such factors are ignored in the design process.

Traffic Signal Priority

Delay at traffic signals causes nearly 50 percent of the delay experienced by transit vehicles.See Evans, H., and G. Skiles. "Improving Public Transit Through Bus Preemption of Traffic Signals," Traffic Quarterly, Volume 24, Number 4, October 1970, pp. 531-543. Traffic signal priority for transit means that traffic signals are designed to provide a green light to transit vehicles whenever possible. There are three approaches to providing transit with priority at traffic signals: passive, active, and unconditional. Zürich has developed a unique form of active traffic signal priority. The three standard approaches and Zürich's approach are outlined below.See Sunkari, Srinivasa, et. al. "Model to Evaluate the Impacts of Bus Priority on Signalized Intersections," Transportation Research Record 1494; Traffic Operations, Traffic Signal Systems, and Freeway Operations 1995; Washington D.C. 1995, p. 117.

Passive Priority

In passive priority systems, predetermined timing plans are used to provide some benefits to the transit movements but do not require the presence of the transit vehicle to be active. The following are specific types of passive priority techniques:

Cycle Length Adjustment -- Reducing traffic signal cycle lengths so that transit vehicles wait less time at intersections.

Splitting Phases -- Splitting a traffic signal's priority phase movement into multiple phases and repeating it within a cycle can reduce transit delays without necessarily reducing the cycle length.

Areawide Timing Plan -- An areawide timing plan provides preferential progression to transit vehicles by designing traffic signal cycle offsets using transit travel times rather than automobile travel times.

Metering Vehicles -- Metering consists of allowing transit vehicles to bypass metered signals with special reserved bus lanes, special phases, or by rerouting transit vehicles to nonmetered signals. Two examples of this technique are known as "queue-jump" and "queue-bypass."

The passive approach is the simplest form of providing transit priority at traffic signals since it simply sets cycle times or phases to reflect the average speed of transit vehicles, rather than mixed traffic. Generally, this is not very effective; however, in cases when multiple transit vehicles use a street, such as San Francisco's Market Street, it can create significant benefits. Furthermore, using traffic signals to meter vehicles can be an effective technique when combined with roadway improvements.

Active Priority

An active priority system provides priority only when a transit vehicle is present. In the United States and Europe, active systems have been used since the early 1970s.See Lin, Guey-Shii, et. al. U.S. Department of Transportation Federal Transit Administration. Adaptive Control of Transit Operations. November 15, 1995, 2-8. Signal preemption is an active system and a complicated type of traffic signal priority program. In these systems, the transit vehicle trips a switch (physical or electronic) or the operator pushes a button on the dashboard that causes an individual traffic signal to interrupt its cycle and give a green signal to the transit vehicle. Interrupts are activated within the signal's minimum safety parameters, such as minimum pedestrian walk times. This approach is used in many cities, especially in conjunction with new light rail transit lines.

The following are specific types of active priority techniques:

Phase Extension -- The traffic signal phase is extended to enable the transit vehicle to travel through the intersection before the traffic signal changes to red.

Early Start -- The traffic signal phase for the transit vehicle direction is started early when a transit vehicle arrives at the intersection during the red phase.

Special Phase -- A special transit-only phase is inserted into the signal cycle's normal phase sequence to allow the transit vehicle to travel through the intersection with minimal delay.

Phase Suppression -- A traffic signal cycle phase with low demand is suppressed from the normal cycle to enable the appropriate phase for the transit vehicle to occur sooner, thus reducing the amount of transit vehicle delay.

A major design issue in active preemption systems is the additional delay caused to other vehicles when changing the traffic signal cycle times to provide priority for transit. Traffic engineering literature cautions that traffic signal preemption should be used only where intersections are "operating at less than saturation capacity, where occasional timing or phasing changes will not significantly degrade the level of service."See City of Portland, Office of Transportation. Transit Preferential Streets Program - Sourcebook; p. 2.

Unconditional Priority

In unconditional priority systems, transit vehicles are priority no matter what phase the current cycle is in, by finishing the required clearance intervals and then providing the phase appropriate for the transit vehicle. This is rarely done for transit vehicles, but it is used for emergency vehicles.

Zürich's Approach

Zürich developed a unique approach that applies the active approach to all the traffic signals in its network. Zürich's system estimates the arrival time of a transit vehicle at an intersection. Next, it optimizes the traffic signal phasing and timing to provide a green signal for transit when the transit vehicle arrives at the intersection based on a "dynamic" approach to the traffic signal network design. Zürich provides transit priority without significantly impacting traffic conditions by carefully determining the right cycle, phasing, and providing green time only when required by a transit vehicle. Research completed in the United States for the Federal Transit Administration supports this type of approach to transit signal priority systems.

According to the report, "Ideally, a really smart signal control system should exploit real-time information about transit operations and general traffic conditions and adapt as efficiently as possible to changing conditions while minimizing disruptions in networks with coordinated signals. In the process of continually revising signal timings it should consider in real time such factors as:

Traffic volumes at all approaches to intersections.

Queue lengths and potential spill-backs that might block lanes or intersections.

Expected arrival times of transit vehicles at signalized intersections.

Expected passenger occupancies of transit vehicles and other vehicles.

Deviations from schedule.

Deviations from proper service headways with respect to preceding and following transit vehicles.

Expected demand and wait times at downstream transit stations.

Expected arrival times of connecting transit vehicles at downstream transfer stations.

Expected delays to transit riders, motorists, pedestrians, and other users that are attributable to signal control decisions.

Expected vehicle operating costs attributable to signal control decisions.

Expected energy consumption and air quality impacts of signal control decisions.

Policy-based priorities that may be specified to create mode choice incentives, such as encouraging transit use." See Lin, et. al., op. cit., p. ii.

The type of signal control system described in this quotation is considerably more high-tech than Zürich's, although Zürich's system addresses the same problems by combining its traffic signal program with other low-tech transit priority techniques. For example, exclusive transit lanes and traffic improvements mean that transit vehicles seldom deviate significantly from schedule, so the traffic signal system does not consider this factor in deciding how to give priority to transit vehicles.

The chapter on See Zürich's Transit Priority Program presents a detailed description of Zürich's approach to traffic signal transit priority.

Transit System Changes

Three specific system-level changes that impact transit speed are operations center, proof of payment, and improved vehicle design. Transit system operations improvements are physical and institutional changes made to the entire transit system to help speed up transit. They can be difficult to implement, because they face many policy and institutional questions and because they need to be implemented over the entire network. However, they can be effective if considered when developing a long-term plan for transit.

Operations Center

The operations center monitors the position of transit vehicles and maintains schedules and reliable headways. When transit headway becomes irregular, vehicles begin to bunch together, causing significant delays and poor service quality. The problem is caused because when transit vehicles become delayed, more people are waiting to board the first vehicle at downstream stops, which further delays the first vehicle, enabling the following vehicle to catch up with the first vehicle.

An effective operations center can provide assistance to transit vehicles operating behind schedule by providing information and direction to operators. Operations centers can reroute vehicles around incidents and place standby vehicles into service.See Lin, et. al., op. cit., p. 7-1.

Operations centers include:

Communications systems -- Provide information and instructions to drivers and passengers.

Vehicle tracking systems -- Provide information on the location of all vehicles in the system.

Plans for addressing system disturbances -- Includes spare vehicles to put into service when needed.

Operations centers enable transit management to improve service by making real-time changes to routing and runs. Both are most effective when the transit system operates in a generally stable condition. It is hard to improve transit service significantly using these techniques when schedules are on the verge of breakdown due to traffic congestion. This is another reason transit priority improvements are most effective when they are implemented in a coordinated and comprehensive manner throughout the transit network.

Proof of Payment (Self-Service Fare Collection - SSFC)

Proof of payment (SSFC) frees the transit driver from collecting fares and enables all vehicle doors to be used for boarding and alighting. This significantly reduces the amount of time that a transit vehicle spends stopped at stations. Most new light rail transit systems in the United States use proof-of-payment systems, while in much of the rest of the world proof of payment is used for all forms of public transit.

Introduction of a proof-of-payment system is complicated and raises fare evasion questions, but experience in Europe shows that these problems can be solved and that proof of payment leads to significant transit travel time savings. Experience with proof of payment in the Portland bus system showed that problems outweighed benefits. As a result, Portland discontinued the trial program. Currently, Portland's light rail system uses proof of payment.See Portland, Sourcebook, op. cit.; p. 24.

Improved Vehicle Design

Specific design improvements include low-floor vehicles, improved interior circulation spaces, and multiple wide doors. Where low-floor vehicles are unavailable, the same benefit can be attained by constructing platforms at the level of the transit vehicle floor as has been done with Curitiba's (Brazil) express bus system. Used in combination with proof-of-payment systems, these vehicle improvements significantly reduce the time a vehicle needs to spend at transit stops. These improvements also make vehicles more comfortable and accessible for all passengers.See Portland, Sourcebook, op. cit., p. 26

Separate Right of Way: Exclusive Transit Lanes

The key question facing all transit system designers is how to make their system fast. Often, speed requires using a right of way for transit only. In most rapid transit systems, this exclusive right of way is an expensive subway or aerial structure. In contrast, the transit priority approach generally consists of redistributing existing street space to provide an exclusive transit lane. Short sections of exclusive right of way also are built in transit priority programs.

This section describes three different types of separate right-of-way improvement: redistributing space on existing roadways for transit, transit malls, and building new transit right of way.

Redistributing Existing Roadway Space for Transit Use

The most common way of creating a separate right of way for transit is to take an existing lane of mixed-flow traffic and designate it for transit use only. These exclusive transit lanes are areas of roadway that can be used only by public transit vehicles. Transit lanes vary from long stretches of roadway to short sections just before intersections. There are numerous variations in the operation and design of these roadways.

In terms of operations, some cities allow taxicabs to use transit lanes (for example, San Francisco and Paris). Often, exclusive transit lanes are only exclusive during certain times of day (for example, peak periods); afterward, they revert to mixed flow or parking lanes. In many cases, private vehicles making turning movements can use exclusive transit lanes. Clearly, this reduces the lane's transit reliability, especially in areas with high numbers of pedestrians, whose crossing movements will delay turning vehicles. Portland's guidelines assume exclusive lanes are shared with turning movements. A condition for application of this technique is that the turn lane must be less congested than the through lanes.See City of Portland, Office of Transportation. Transit Preferential Streets Program -- Sourcebook; 1997, 8.

In physical terms, there are many different ways of designing an exclusive transit lane to meet the particular needs and specific roadway conditions at the site. The most straightforward type of transit-exclusive lane is simply a stretch of roadway that is set off in some way for use by transit vehicles only. For example, a transit lane can be a contraflow lane in the underutilized roadway direction.

A second type of improvement combines roadway changes with traffic signal technology to enable transit vehicles to be the first to enter a stretch of uncongested roadway. Two common methods are queue bypass and queue jump. Queue bypasses are short sections of exclusive roadway located near an intersection that enable transit vehicles to bypass congestion at the intersection. Queue jumps are queue bypass physical improvements with the addition of a change in traffic signal timing that enables transit vehicles to start ahead of private vehicles -- essentially jumping ahead of them. Several interesting Zürich examples of these techniques are described in See Zürich's Transit Priority Program

A critical aspect in the design of exclusive transit lanes is traffic lane separation. Building a new exclusive separate right of way is the ideal solution. However, an exclusive transit lane can be created by painted lines. A major difference between these is the level and type of enforcement necessary to keep them exclusive. Physical separation has higher capital costs, but is generally self-enforcing. Reliance on painted lines or signs requires much greater enforcement in order to be effective.

Relaxation in the control and enforcement of bus-only lanes has been identified as a key element in the gradual discontinuance of bus priority improvements implemented in the 1970s.See Vuchic, et. al., op. cit., p. 11 It is interesting to consider whether it is easier politically to get an exclusive transit lane for light rail than for bus projects.

A key implementation issue for exclusive transit lanes is how much they are used by transit. If a transit lane is not well used, motorists may perceive it as wasted space and complain to elected officials. Given the importance of support for implementation of these improvements, it is critical that planners consider introducing exclusive transit lanes only where they will be heavily used. This requires creative techniques to bypass only congested areas and considering rerouting other transit routes so that several use the same stretch of exclusive right of way.

Special Case: Transit Malls

Transit malls are sections of street, generally located in a city center, where many different transit lanes operate with little or very limited private traffic. While transit malls are often thought of in terms of their contribution to urban livability, they also serve two important transit priority functions: They speed service by reducing interference with private traffic, and they provide a good opportunity to implement systems-level transit priority improvements.

Transit malls provide a good opportunity to implement system operations improvements because they can serve as linear transit interchange stations providing patrons with a convenient place to change from one route to another, thus speeding their trip. This is especially true when the transit system operates on a pulse-type schedule, that is, where several different transit routes are scheduled to arrive at the transit mall simultaneously, allowing passengers to transfer between the routes efficiently.

Furthermore, transit malls encourage such improvements as better marketing. Malls make transit more visible to the public and provide better passenger information, introduction of passenger amenities at transit stops, and innovative fare programs (for example, fare-free zones).

Transit malls must be carefully planned and designed. There are many excellent examples of transit malls in the United States, but also several failures that resulted when the factors needed to make a transit mall successful were not fully understood.

Transit malls are constructed as elements in new light rail transit systems. New, well-designed transit malls, including those in San Jose, Portland, and Denver, are good examples of high-quality urban design and transportation planning.

Building Separate Right of Way for Transit

Building a separate right of way (for example, a busway) is a costly transit priority improvement, especially if it serves as the catalyst for implementing other transit priority improvements. Furthermore, even given their high cost, these improvements can be less expensive than traditional transit capital solutions like building entirely new light rail or Metro systems.

Building a separate right of way for transit is most like a transit priority improvement when it is designed to speed up service in a particular geographic area. As a result, it can be used by several different transit routes and when a comprehensive transit priority program is implemented on the surface sections of the transit routes (for example, a subway in a downtown area).

The best examples of these types of improvements are bus rapid transit systems and light rail systems that share major capital facilities. Bus rapid transit systems are attractive and considered less expensive to build than rail. Boston and San Francisco have benefited greatly by placing the downtown sections of their light rail networks underground.

IMPLEMENTATION OF TRANSIT PRIORITY TECHNIQUES

The effectiveness of a transit priority program often depends more on the degree or extent to which transit priority techniques are implemented than on the specific improvements that are implemented. This section outlines four different levels of implementation and describes the special case of how building a bus rapid transit system can serve as the catalyst for implementation of a transit priority program.

Transit Priority Program Implementation Levels

This research defines four different implementation levels for a transit priority program, ranging from limited application of individual improvements to comprehensive application of a full range of improvement types throughout the network. The four levels are shown in See Levels of Implementation for Transit Priority.

Levels of Implementation for Transit Priority
Level	Improvements
Limited	Specific Locations
Route Level	Entire Route
Areawide	Specific Points
Comprehensive

FHWA/CA/RM-2000/09

Executive Summary 1

Introduction 17

Transit Priority 21

Zürich Context 39

History: Zürich's Transit Priority Program 51

Zürich's Transit Priority Program 73

Complementary Transportation
Programs 93

Public Support for Transit
Improvements 111

Implementation Lessons from Zürich 125

End Notes 137

Acronyms and Abbreviations 143

Bibliography 145

About the Authors 149

List of Tables

Executive Summary

Introduction

REPORT ORGANIZATION

RESEARCH METHODOLOGY

Transit Priority