This report summarizes results from the evaluation of nine ITS implementation projects in the city of San Antonio, Texas. As with many other urban areas, San Antonio is experiencing significant growth in both population and travel demand. The nine projects undertaken during this initiative seek to assist the existing transportation infrastructure in accommodating the growth. The evaluation report summarizes analysis of the impacts of each project in the areas of system efficiency, customer satisfaction, safety, and fuel consumption. San Antonio had a relatively extensive implementation of ITS prior to this study and, consequently, the incremental benefits experienced in San Antonio through expansion and additions to the existing system may be somewhat smaller than the benefits that could be achieved in areas with little prior implementation of ITS.

The evaluation report contains benefits information regarding the implementation of an incident management program and dynamic message signs (DMS) along a freeway corridor and traffic signal timing control operations along a parallel arterial. Through a modeling effort, the study investigates the impacts of each implementation individually, and the combined impact of integrating the DMS with incident management and integrating both the DMS and incident management with traffic signal timing plan alterations along an alternative arterial route.

Results indicate that the most effective stand-alone implementation is incident management, recording improvements in all impact measures assessed. DMS and arterial traffic signal control can provide additional improvement under many of these areas. For the particular corridor modeled during this study, optimum implementation of the integrated DMS and incident management result in a 5.7 percent decrease in delay, a 2.8 percent decrease in crashes, and a 1.2 percent decrease in fuel consumption annually. Integrated use of incident management, DMS and arterial traffic control can achieve an annual benefit of a 5.9 percent reduction in delay, a 2.0 percent decrease in crashes, and a 1.4 percent decrease in fuel consumption for travelers in the corridor. Focus group studies indicate that customers are satisfied with the DMS system, but do have some suggestions for improvement. Participants in the focus groups felt that DMS were a reliable source of traffic information, primarily due to their proximity to the congestion or incident. A similar study was ongoing for the signal control systems at the time of this report.

Additions and improvements to elements of San Antonio’s traveler information system include new traveler information kiosks, improvements to the internet web site, and the installation of In-Vehicle Navigation (IVN) devices in vehicles operated by public agencies in the San Antonio area. The kiosks provide information on incidents and congestion on the freeway network, transit schedules and fares, as well as navigational assistance. The web site provides freeway traffic information including incident locations, and links to transit schedule and fare information. The IVN devices provide navigational assistance, incorporating information on congestion, incidents and railroad crossing status when planning trips.

Evaluation of the kiosks by a qualified expert indicated that the devices had several functional problems and were unlikely to be used often by travelers. Based on these results, the study did not perform further evaluation on the system impacts of the kiosks or customer satisfaction with them.

The web site evaluation indicates that usage of the site was increasing at a rate of 19 percent per year over the course of the nine-month evaluation period. Significant latent demand for the service was evidenced by spikes in the number of users accessing the site during two severe weather events over the evaluation period. Despite this growth, the relatively small number of travelers making use of the system lead to no overall system impacts due to the web site. Modeling results indicate that individual travelers who use the web site prior to traveling along a particular corridor would receive annual benefits of a 5.4 percent reduction in delay, a 0.5 percent reduction in crash rate, and a 1.8 percent reduction in fuel consumption.

The small number of publicly owned vehicles using the IVN devices led to no system impact from these devices. Focus groups composed of drivers of vehicles equipped with the units indicated that the drivers most satisfied with the system were those that frequently drove different routes each day. Drivers often asked to drive to unfamiliar parts of the metropolitan area, such as paratransit drivers and police investigators, seemed to get the greatest benefit from the system. Public safety representatives did indicate that, with improvements to the method for entering destinations, the devices could be helpful in reducing response times of emergency vehicles. Modeling results indicate significant potential benefits for individuals using the devices. Over a one-year period a traveler using an IVN device could experience an 8.1percent reduction in delay, a 4.6 percent reduction in the crash rate, and a 3 percent reduction in fuel consumption.

The San Antonio project also included a demonstration implementation of a telemedicine system, known as LifeLink, allowing video and teleconferencing between emergency medical technicians (EMTs) and doctors at nearby hospitals. The system allowed doctor’s to see video images of the incoming patients and provide advice to the EMT in the ambulance on providing care en-route to the hospital. Though the system had no impacts on the measures of delay or energy consumption, significant safety impacts are likely if the system is applied in rural areas. As applied in an urban area, the short transit time to the hospital limited the additional benefit of LifeLink. EMTs were very satisfied with the system, though doctors had concerns with the system, especially since it required them to leave other tasks at the emergency room.

San Antonio also implemented a program to increase traveler awareness of highway-railroad intersection blockages. The system was designed to display messages on a freeway DMS regarding the delay due to a railroad crossing just beyond an exit ramp. As implemented under current traffic conditions, this system had no impact under any of the measures. However, with increased demand and a slightly modified operating strategy, modeling indicates that a 6.7 percent decrease in system delay, 8.7 percent decrease in crashes, and a small reduction in fuel consumption are possible during each 6-minute train crossing.

The San Antonio project also investigated an improved travel data server containing information from the various ITS components operating in the area. The server had no direct impacts on the operation of the transportation system, but did provide necessary inputs to the multimodal traveler information system. Travelers were satisfied with the system, but requested additional data regarding arterials.

The final component of the San Antonio deployment initiative was a system using volunteer private vehicles equipped with radio transponders as probes to determine travel times along area roadway segments. Over 40,000 people volunteered to use the tags on their vehicles, indicating strong support for the project. The information provided had no direct impact on network efficiency, safety, or energy consumption.

The evaluation reports contains several conclusions and recommendations drawn from the results above, and discussions with various stakeholders within the projects:

• A successful ITS deployment requires a strong institutional framework.
• The combined benefit of integrated ITS components may not equal the sum of individual implementations, however this integration can offer improved benefits and costs over isolated deployments. For example, the reduction in delay possible along a particular corridor during a major incident was 16.2 percent with and incident management system operating alone, 4.6 percent with only a freeway management system, 2.8 percent with only an arterial management system, and 19.9 percent with all three systems implemented in coordination. It is also important to integrate the three systems described above in a strategic fashion. Applying all three systems to every incident, regardless of severity, can decrease the overall benefit of the systems by encouraging travelers to unnecessarily change their travel plans during minor incidents.
• Integration with existing system components can also significantly reduce implementation costs. The LifeLink project would have been considerably more expensive without the use of the existing roadside fiber-optic lines installed for the freeway management system.
• Pre-trip ATIS services, such as San Antonio’s TransGuide web site, can reduce delay, crash risk, and fuel consumption in a manner similar to traffic management applications.
• Kiosks appear to have a smaller market and greater implementation difficulties than web sites.
• Public agencies may benefit from in-vehicle navigation (IVN) devices. Proper training, maintenance and equipment selection is essential for agencies to benefit. As implemented in San Antonio, users complained of the difficulty in inputting destinations easily. Sixty (60) percent of users did report that it was easier to find unfamiliar addresses with the devices, that they saved time and felt safer to use than paper maps. Paratransit operators found the devices very useful and some operators now refuse to take out buses that are not equipped with the system.
• Emergency telemedicine can save lives and reduce treatment and transportation costs. A number of institutional and technical issues must be addressed in order to maximize these benefits.
• Institutional issues may impede the development of systems designed to prevent train-automobile crashes at highway-rail intersections. Less intrusive systems might be able to reduce auto-auto collisions, but the current traffic demands and train delays in San Antonio do not illustrate these benefits.
• Vehicle probes offer a potential means of offering travelers the additional arterial information they desire. This will only be possible if a significant market penetration of probe vehicles can be attained.
• Travelers prefer roadway condition information provided through camera images whenever possible; internet pages with these types of information are among the most visited at traveler information sites that provide them.

The evaluation report contains more detailed explanations of the findings for each of the projects carried out during the San Antonio Model Deployment Initiative.

Notes

See Also:

Advanced Warning for Railroad Delays in San Antonio, Lessons Learned from the Metropolitan Model Deployment Initiative,2000.

Science Applications International Corporation. San Antonio's Medical Center Corridor: Lessons Learned from the Metropolitan Model Deployment Initiative. U.S. Department of Transportation. Washington, DC: 2000.

Science Applications International Corporation. Evaluation of the San Antonio Metropolitan Deployment Initiative.
Paper presented at the 7th Annual World Congress Conference, Turin, Italy. November 2000.