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Through presentations and discussions with the European host countries, the scan team discovered several common, overarching challenges and issues facing the countries. These challenges include an increase in travel demand, a growth in congestion, a commitment to safety, and a shift in agency culture toward active management and system operation that focus on the customer, the willingness to use innovative strategies to address congestion, and the reality of limited resources to address all of these challenges. These issues resonated with the scan delegation as they represent a state of transportation that mirrors that in the United States.
All across Europe, demand for transportation infrastructure is growing. In Germany alone, ADT has grown significantly between 1975 and 2000 on the entire 12,000-km federal motorway network.(21) Furthermore, forecasts predict that the demand for road transport will increase 16 percent for individual passenger vehicles between 1997 and 2015 and 58 percent for freight transport over the same period.(21) Similar trends are seen in the Netherlands. Demand in that country is expected to grow at an average rate of 2 percent a year for the next 20 years.(67) As demand increases on critical links on the European road network, agencies work to identify ways to best meet that demand in an efficient and cost-effective manner.
Often, Americans do not consider U.S. and European transportation networks on equal footing. They assume European cities have extensive public transport facilities that, when combined with higher fuel prices and denser urban development, help keep automobile ownership and related congestion at a more modest level than in the United States. However, the scan revealed that Europe and the United States face the same challenges. Despite higher fuel prices, public transit services that are fairly widespread, and significant use of alternate modes, automobile ownership is rising and congestion and air pollution are increasing in Europe.
The Netherlands is typical among European countries in its experience with increasing congestion. Figure 57 illustrates the impact of congestion growth on the Dutch roadway network over the past three decades. Bottlenecks on the system have increased since the 1970s, and they now pose a considerable threat to overall mobility for the motoring public. Because of these network failures, the Ministry of Transport, Public Works, and Water Management established an organizational policy in 1994 focusing on maintenance, more efficient use of the roadway network, and road widening. This policy has directed organizational funding and activities ever since.
Figure 57: Congestion growth in Rotterdam, Netherlands.
A major attitude shift in the way European countries approach congestion management is the importance they place on the roadway user as a customer. Every country visited places significant emphasis on improving travel time reliability and keeping the roadway user informed of roadway conditions. In Germany, for example, the government has a goal to ensure that 80 percent of all journeys are served with adequate, standardized real-time traffic and traveler information services by 2010. This goal is part of a mobility management strategy that focuses on service to society and users.(21) In the Netherlands, the government's goal is to ensure predictable and acceptable travel times for users, focusing on having a maximum travel time under congested conditions of no more than twice that under uncongested conditions in urban areas and having 95 percent of all trips occur on time.(44) These countries understand the importance of public buy-in to traffic management. They acknowledge that users want to know why their speeds are being reduced or why they should divert to alternate roadways. Furthermore, they work to develop the trust of users through legitimate and reasonable speed limits to gain their cooperation in the overall management of roadway congestion.
In Denmark, the Road Directorate believed so strongly in the importance of engaging those impacted by the M3 expansion that they hired a journalist and two additional staff members to handle the public relations work that involved residents and employers in the corridor. The agency's residential and employer-based communications were geared toward communicating with customers located in the construction zone itself. It has kept landowners informed of the project's progress, including any delays and changes that may affect them. The open dialogue with and involvement of both landowners and users have helped keep complaints to a minimum. In the United Kingdom, the Highways Agency puts customers first in its business plan and has a customer-focused frontline operation of the strategic road network.(68) The Highways Agency sees the roadway user as an integral part of the system. The organization's three-pronged theme reflects this acknowledgment: "Safe roads, reliable journeys, informed travelers." Thus, the agency places the importance of communicating with the public on equal footing with saving lives and providing reliable trips on its network. In all of the countries visited, active management is a component of the customer approach to operating the roadway network.
Operating under the conditions mentioned previously, European transportation agencies are seeking new and innovative ways to optimize performance of the existing system and harnessing the power of advanced technologies to help accomplish their goals. Using such active management operational strategies as speed harmonization, temporary shoulder use, ramp metering, and dynamic route information—either alone or in combination—the countries are using advanced technologies to instrument congestion networks to improve throughput and increase safety. Most of these countries are no stranger to innovation. The Netherlands implemented its first speed harmonization system in 1981.(45) This operational strategy is now one component of a comprehensive traffic management architecture, shown in figure 58, that centers on implementing various control, operational, and construction components to ensure performance measures are met on a regional basis across the country.
Figure 58: Traffic management architecture for the Netherlands.
In the 1970s, Germany implemented the operational strategy of speed harmonization to stabilize traffic flow under congested conditions.(69) Furthermore, Denmark has taken the innovative approach of using this operational strategy during a major construction project and will later make it a permanent installation along the corridor. Public-private partnerships are also becoming a well-accepted strategy for transportation finance, allowing agencies to outsource operations through stringent contracts that include performance-based incentives, thus ensuring that roadway users' needs are met effectively. These strategies and others, discussed later in this document, illustrate the fact that these countries are continually searching for innovative ways to improve safety and travel reliability and make the most of their existing infrastructure.
Safety and the reduction of incidents and incident severity are of utmost importance in the countries the scan team visited. For example, Germany implemented its first motorway queue warning system in an effort to reduce incidents. The result has been safer driving by motorists because they are aware of oncoming conditions and approach the end of a queue with caution.(21) In addition, "safe roads" is the first part of the Highways Agency mission, a testament to its commitment to reducing roadway fatalities and major injuries by a third over the next 2 years while balancing safety and the environment with the need to travel.(68) Also, national and regional traffic management centers are operational in all of the countries visited, each focused on traffic safety and disseminating traveler information to motorway users. It was clear to the scan team throughout its visit that the safety of network users was the highest priority and that all of the operational strategies deployed were structured to accomplish their intended optimization objective in the safest manner possible.
All across Europe, countries have limited resources to address the growing travel demand and congestion problems they face. Hence, cost-effective use of limited funds is paramount and typically illustrated in governmental policy. In the Netherlands, for example, the governmental mobility policy has a three-pronged approach of improving the infrastructure, improving road use, and improving and streamlining internal procedures.(44) Improving road use centers on the national management of work zones, effective incident management, and improved traffic information. These policy objectives point to the need to make the best use of the existing infrastructure, reduce waste, and concentrate infrastructure improvements on new connections, widening, and extra or designated lanes.(44) In England, the M42 Active Traffic Management Pilot Program is a proactive management strategy that is less expensive than widening, thereby making the most of the available road space and using fewer resources.(51)
Given the overwhelming similarities between congestion growth in Europe and the United States, the scan team identified seven key approaches to congestion management that have the potential to help ease congestion in the United States. While some strategies have been already implemented in some form in the United States, adopting unique aspects of their European implementation can enhance their impact, maximize the efficient use of existing facilities, and ensure that future planning efforts optimize the use of limited resources to address congestion. Furthermore, a critical component of the strategies is the presence of regional traffic management centers that are operationally integrated and interoperable with a national traffic management center that manages the roadway networks from a network-wide perspective. This coordination helps ensure that management strategies deployed in one region do not negatively impact other regions and that they foster a holistic approach to congestion management within the country and beyond its borders.
A major weapon that most European countries use in the battle against congestion is active traffic management. This operational strategy works to provide reliable trips, reduce recurring and nonrecurring congestion, and provide enhanced information to drivers.(58) Building on advancements in technology and traffic management experience, this strategy works to make the best use of the existing capacity and provides additional capacity during periods of congestion or incidents. Active management falls into the two categories of that for recurrent and that for nonrecurrent congestion. The following sections highlight the specific applications of active management the scan team identified as having the most potential for successful application in the United States.
The primary strategies for actively managing recurrent congestion are speed harmonization and temporary shoulder use. The application of these strategies is mostly consistent across the countries the team visited, with some differences in the specific signs deployed to convey the active management strategy to road users. The following sections summarize the application of these strategies in various countries and address the unique differences in their application.
As noted earlier, the European countries the scan team visited recognize that reducing speeds under congested conditions not only improves overall performance but reduces the likelihood of primary incidents. Through speed harmonization, agencies make the most of existing capacity by delaying the point at which flow breaks down and stop-and-go conditions occur. Under speed harmonization, an expert traffic management system monitors travel data from an instrumented roadway. Once travel speeds and traffic volumes reach a certain threshold set by the system's algorithms, the system automatically begins to reduce speeds incrementally across all lanes along the motorway upstream of where the congestion is heaviest.
The intent of speed harmonization is to extend the time that efficient travel is available to users. Sign gantries spanning the facility provide speed limit information and varying additional information, depending on the specific country's implementation. The speed harmonization systems are configured primarily to automate the deployment. The expert system in place in the traffic management center monitors data coming from sensors in the field and automatically triggers the deployment of the speed harmonization system when congestion thresholds are exceeded and congestion and queue formation are impending—all without requiring operator intervention. This is considerably different from the U.S. approach, in which agencies rely heavily on operators to manage the system and deploy management strategies manually.
In Denmark, the Road Directorate of the Danish Ministry of Transport and Energy deployed speed harmonization as part of work zone traffic management strategies for the multiyear widening of the M3. Using traffic detection systems, CCTV cameras, and DMS operated by control center staff in the region, traffic is monitored and speeds are reduced when congestion begins to build. This active management strategy has been deemed a success by Road Directorate and project staff. As a result of speed harmonization, incidents on the motorway have not increased during the reconstruction project, while the existing two lanes have been maintained at a narrower-than-normal width and no entrance ramps, exit ramps, or bridges have been closed.(39)
The Netherlands has used speed harmonization for many years. Some deployments have been implemented to promote safer driving during adverse weather conditions (such as fog), while others have been used to create more uniform speeds. The Netherlands' Motorway Control System provides lane control and speed limit signs generally every 500 m and is used to slow traffic in advance of a slowdown, shock wave, or work zone. The system has reduced collisions by about 16 percent, increased throughput 3 to 5 percent, and reduced the cost of work zone traffic control. The standard speed limit is 120 km/h on the motorways, but variable posted speeds can drop to as low as 50 km/h if an incident occurs. Speed harmonization in Germany, known locally as line control, has been in use since the 1970s. It is geared toward improving traffic flow based on the prevailing conditions and is deployed on motorway sections with high traffic volumes.
Temporary shoulder use is a congestion management strategy typically deployed in conjunction with speed harmonization. The strategy provides additional capacity during times of congestion and reduced travel speeds. In Germany, the right shoulder has been used during peak travel periods since the 1990s.(27) This use of shoulders is part of several traffic control systems developed by the Federal Ministry of Transport and applied in various locations in the country.(28) In England, the first deployment of temporary shoulder use is part of a comprehensive traffic management system that also involves speed harmonization. A critical component of the M42 system is the installation of emergency refuge areas at 500-m intervals along the shoulder, each equipped with an emergency call box.
The Netherlands, in addition to allowing temporary use of the right shoulder, also deploys temporary use of the left shoulder under congested conditions. The left lane, or plus lane, is opened for travel use when traffic volumes reach levels that indicate congestion is growing. As in Germany, temporary use of the left lane is allowed only when speed harmonization is in effect. Additional facilities implemented to mitigate any adverse safety consequences of temporary shoulder use include overhead lane signs, emergency refuge areas with automatic vehicle detection, speed reduction, variable route signs at junctions, advanced incident detection, CCTV surveillance, incident management, and public lighting.(49)
A variation of temporary shoulder use deployed in Germany is junction control, a combination of ramp metering and lane control at on-ramps.(30) Typically, the concept is applied at entrance ramps or merge points where the number of downstream lanes is fewer than upstream lanes. These strategies for managing recurrent congestion work to make traffic flow more uniform. They maximize use of the existing capacity, while temporarily adding to that capacity in a manner that does not increase roadway safety hazards.
While speed harmonization and temporary shoulder use are congestion management strategies for recurrent congestion, European countries also implement them for nonrecurrent congestion. They are powerful tools for providing better operations during incidents along the motorway. In addition, the Europeans use active rerouting to provide alternate travel information for roadway users during incidents. Germany uses dynamic message signs and rotational prism guide signs to provide alternate route information during incidents, both of which adapt to appropriate lane designations when temporary shoulder use is in effect. Dynamic rerouting, a traffic message channel, and standardized messages for DMS are part of a comprehensive German approach to serve 80 percent of all trips with real-time traveler and traffic information by the year 2010.
Providing alternate route information is also a critical component of the regional traffic management centers in England. When major incidents create significant delays on the motorways, center personnel coordinate with the National Traffic Control Center and local authorities to ensure that diverted traffic will not negatively impact the local road networks. This coordinated provision of detailed alternate route information helps reduce nonrecurrent congestion and provides better travel experiences for motorway users.
One particular fact the scan team noted is related to deployment of detection technology for active management purposes. In most of the countries the team visited, loop detectors were installed on instrumented freeway corridors at shorter intervals than in the United States. Depending on the country, detectors are installed every 500 to 1,000 m, and reliability of these detectors is very high because of dedicated resources to maintain them and routinely replace faulty ones. The high density of detection provides operators with a detailed, comprehensive assessment of facility conditions and helps serve as the data backbone for automated systems. In addition, CCTV equipment is installed at closely spaced intervals to quickly and reliably check shoulders for clearance before implementing temporary shoulder use without having to conduct a physical inspection on the ground. Finally, these technology deployments support incident management operations, discussed in the next section.
A key component of the customer approach to congestion management in Europe centers on the need to ensure travel time reliability. Related to that reliability is the impact nonrecurring congestion has on travel time. European countries recognize the major role nonrecurrent congestion plays in overall urban delay. As in the United States, nonrecurrent congestion makes up anywhere from 40 to 60 percent of all congestion on urban motorways, a significant portion of which is a result of incidents. As figure 59 shows, statistics in Germany indicate that nonrecurrent congestion in the form of work zones and incidents accounts for 61 percent of travel time losses on German motorways. Thus, European countries acknowledge that swift response to incidents is critical to managing congestion, reducing the occurrence of secondary incidents, and focusing on the needs of roadway network users. Moreover, they recognize that reducing speeds under congested conditions not only improves overall performance but reduces the likelihood of primary incidents.
Figure 59: Causes of lost travel time on German motorways.
In Greece, Attica Tollway operators employ a comprehensive system for handling incidents, the primary objective of which is to enable quick intervention in incidents while providing high-quality services that ensure optimum traffic conditions. The 24-7 operations are undertaken by personnel critical to the efficient provision of assistance to incidents and the quick remedy of any problem. They maintain constant communication with personnel in patrol units who are the first responders to tollway incidents. Their commitment to efficient incident management is a testament to their commitment to provide high-quality service to customers and enhance mobility around Athens. The Highways Agency in England has a similar program that began as a pilot in 2004 with full deployment expected by the end of 2006. The Traffic Officer Service consists of trained personnel who tackle congestion by patrolling motorways 24 hours a day, 7 days a week to assist motorists involved in incidents. A unique aspect of the program is that the officers have powers under the Traffic Management Act 2004 to stop and direct traffic or temporarily close lanes or roads.(55) Thus, police officers can concentrate on investigating the incident, which can help reduce its overall duration. The Highways Agency estimates that 25 percent of all congestion on England's motorways is caused by incidents, and the Traffic Officer Service aims to cut incident-related congestion by focusing on moving traffic around incidents as quickly as possible.(55)
Several countries visited also have a congestion or queue warning system integrated with their active management systems. In Germany, this system involves the display of a pictograph on the DMS that indicates congestion ahead. It is also displayed in conjunction with speed harmonization and alerts motorists to reduce their travel speed as directed by the overhead gantries. In the Netherlands, travelers are alerted to congestion by flashing lights on the variable speed limit sign. Like the strategies mentioned above, the warning systems are intended to reduce the occurrence of secondary incidents caused by recurrent or nonrecurrent congestion. While these incident management strategies are not significantly different from those used in the United States, they do represent a critical component of each country's broader approach to addressing congestion, their commitment to serving customers and providing them with reliable travel times, and their recognition of the link among incidents, their duration, and their impact on mobility.
In an era of limited resources, active traffic management is a significant drain on the limited funds an agency has available each year. However, the Europeans recognize the importance of their investment and the need to fund the operation of deployed systems to realize the benefits of that investment. Thus, transportation and traffic management operations are a priority in planning, programming, and funding processes for transportation. To this end, the Netherlands developed the Handbook for Sustainable Traffic Management to help road authorities identify the best way to address transportation needs in a sustainable manner.(71) It serves as a link between the Dutch National Traffic Management Architecture and the accessibility needs of transportation users. Geared to personnel working at the policy level, it addresses the objectives of traffic management and assesses the costs and benefits of those investments to ensure sustainability and improved traffic operations.(71)
As in the United States, European countries struggle to address growing congestion with increasingly limited resources and environmental restraints. All of the countries visited accept the fact that their ability to undertake major expansion projects on congested motorways is limited. Hence, they search for innovative ways to invest their limited resources.
The Federal Highway Research Institute (BASt) in Germany has developed a software tool to conduct an economic assessment on the implementation of temporary shoulder use on congested motorways.(29) This software tool has a general framework that measures the various costs and benefits of temporary right-shoulder use to determine project viability and economic effectiveness. These costs include capital investment, maintenance, traffic safety and incidents, speeds and travel time, and emissions.(29) The software (shown in figure 60) can assess numerous temporary shoulder-use applications at once to help identify the most effective locations for implementation. Once the user inputs the various data required of the software, the tool weighs costs against positive impacts to arrive at a benefit-cost ratio for each potential application. The agency can then select locations for implementation that have the best benefit-cost ratio and represent the best investment of limited resources.
Figure 60: Economic assessment tool for temporary shoulder use in Germany.
The Ministry of Transport, Public Works, and Water Management in the Netherlands takes an even broader approach to assessing the impact of transportation investments. The LMS model, which stands for the National Model System for Traffic and Transport, is a tool the Dutch Ministry uses to strategically appraise different policy packages related to transportation.(46) Taking into account such factors as car ownership and trip characteristics, LMS—which is based on the traditional four-step planning model—serves as a strategic model for the entire country. Over the past 20 years, the ministry has used this model to assess the impacts of the entire transportation investment program for the country, influencing policy decisions at the national level.(46)
The Europeans, like Americans, struggle to manage increasing congestion with limited resources. Public-private partnerships (PPPs) and similar innovative financing approaches are emerging as strategies to solve the ever-growing funding shortfall. England has had such success with PPPs in all sectors, including transportation, that agency officials have identified critical factors important for long-term sustainability and benefit of such collaborations. For example, the Highways Agency is very selective of which projects it slates for PPPs—such as the construction and operation of the National Traffic Control Center—and notes that the majority of benefits on transportation PPPs are realized in operations and maintenance savings over the life of the contract (up to 70 percent over 30 years).(72)
The inclusion of performance thresholds in the payment contract is essential to a successful project. Transportation-based performance measures tied to contract incentives include improved operations, reduced delay, fewer incidents, and similar measures important to users. Improvements on these measures can mean more money for the concessionaire, while such measures as substandard pavement and poor operations during winter events can cost the concessionaire.(45) The result is a PPP that holds the concessionaire accountable for operations and ensures that public resources are spent with the best interests of users in mind. In almost cases, concessionaires combine private funds with some level of public financial contribution for project investment packages.
With the establishment of the European Union, travel between European countries has risen dramatically. Hence, providing consistent messages to roadway users is more important than ever to reduce the impact of congestion on those travelers. All of the European countries have adopted the symbology policies established by the Vienna Convention, so roadway users can expect to see the same symbols on transportation facilities across Europe. This consistency has been applied to emerging technologies, such as electronic toll collection (ETC). As figures 61 and 62 show, ETC signs in Greece and Denmark, while not the same color, both use symbols featuring emitting radio waves. The symbol for an attended toll booth is also similar. Thus, users familiar with any ETC-related facility can easily identify which lane to use to pay their toll. Interoperability across countries is also a working goal for those countries the scan team visited.
Figure 61: Toll-related signing in Greece.
Figure 62: Toll-related signing in Denmark.
Similar consistency is also seen across Europe for indicating variable speed limits to motorists. As shown in figure 63, speed limits are displayed on a DMS panel with a red circle. The display shown here is identical to those used in Denmark and Germany.
Figure 63: Variable speed limit displays in the Netherlands.
Tolling and pricing are being considered in most countries across Europe. However, the underlying purpose of most of these strategies is overall financing of the roadway network rather than congestion management. The Attica Tollway in Greece is a lucrative toll facility that brings in significant revenue each month while working to reduce traffic on the other parts of the Athens roadway network. The first facility of its kind in that part of Europe, it has been an operational and financial success and will most certainly chart the way for additional facilities in the region.
Germany implemented heavy goods vehicle tolling on its motorways in 2006 to accomplish several objectives, one of which was to guarantee the financing of new roads and overall network maintenance.(34) Other motivations for this electronic toll system are to create a pricing scheme borne by the originators of road demand, create an incentive to change the modal split for freight, enhance the efficient use of trucks, and promote the implementation of innovative technology.(34)
Road pricing for all users is becoming more prevalent in Europe. Of the countries the scan team visited, the Netherlands and the United Kingdom are seriously considering implementing road pricing for the entire country in the near future. The success of congestion charging on urban streets in central London has illustrated that pricing potential. Essentially, it is seen as a smarter and more credible long-term option for maintaining the infrastructure and ensures that users pay an appropriate share based on their roadway use.(64) It is clear that road charging is on the horizon in Europe and may be the long-term solution to transportation finance shortfalls and localized congestion management.
One purpose of this scan was to seek information on how agencies approach highway congestion and how they plan for and design managed lanes at the system, corridor, and project or facility levels. As evidenced by the scan team's findings, the European countries visited are aggressively looking to active traffic management systems and other strategies to address highway congestion, but have limited applications of managed lanes as defined in the United States. Most applications that would qualify as managed lane facilities in the United States are in the form of bus lanes and actively managed temporary shoulder use combined with speed harmonization. However, use of managed lanes as a congestion-management tool is gaining momentum in Europe, particularly in the United Kingdom where HOV projects are under development and as lessons learned about managed lanes emerge from the U.S. experience.
The countries in Europe the scan team visited have a comprehensive approach to managing congestion that can easily incorporate managed lanes—as defined in the United States—to help meet mobility and safety goals. Primarily speaking, the infrastructure is already present to manage and operate managed lanes in corridors where active management has already been implemented. The addition of a managed lane strategy can be easily supported and optimized since these corridors are heavily instrumented and users are already familiar with dynamic operating conditions that reflect congestion levels. The governments' commitment to infrastructure investment and technology in managing congestion lays the groundwork for moving toward managed lanes as congestion and travel demand increase in the future. Furthermore, implementation of speed harmonization and temporary shoulder use would most likely be key companions to managed lanes, as they reinforce the efficient use and optimization of the existing network.
The commitment to the user and the presence of 24/7 operations for traffic management facilities and active congestion management also support the future implementation of managed lanes in Europe. Regional and national traffic management centers combined with comprehensive traveler information systems help provide motorists with accurate information about roadway conditions. This ability will be especially critical as managed lane strategies become prevalent and eligibility criteria vary according to changing travel conditions in a dynamic manner. Accurate information about operational strategies will be critical to ensuring the success of managed lanes. Supporting this information dissemination is the European movement to standardize active management, including consistent signing, pavement marking, operations, and geometric design. Consistency across jurisdictions helps reduce user confusion and helps optimize the potential of managed lane facilities. When actively managed, managed lanes can help agencies provide travel time reliability at any time of the day on any day of the year.
Managed lanes are on the horizon in Europe and facets of them are already being deployed. The temporary use of the shoulder sets the stage for the flexible use of the cross section, which is a cornerstone of managed lane operations. Speed harmonization supports the optimization of pavement use and helps increase throughput during times of congestion. In addition, the use of managed lanes to address bottleneck problems, vehicle restrictions, and the potential benefits of pricing and occupancy-based strategies all indicate a movement toward managed lanes. As agencies plan and develop major motorway improvement projects, active management and managed lane strategies are becoming part of the decisionmaking process. Furthermore, agencies are integrating managed lanes and strategies that accomplish similar goals and objectives into their overall agency policies, strategic plans, and planning processes. Thus, as congestion becomes an ever-increasing problem and travel demand grows, Europe has the tools readily available to easily integrate managed lanes into its approach to congestion management.
Europe faces similar mobility challenges as the United States, including an increase in travel demand, growth in congestion, a need to improve safety, and the reality of limited resources to address these challenges. Given these similarities, the scan team identified seven key approaches to congestion management that have the potential to ease congestion in the United States. The purpose of this scan was to examine the congestion management programs, policies, and experiences of other countries and to seek information on how agencies approach highway congestion and plan for and design managed lanes at the system, corridor, and project or facility levels. The following are the critical findings and observations of the scan team in response to this charge:
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