Background: In order to effectively serve the traveling public, most transportation agencies have objectives related to the performance of the freeway system. Performance measurement uses statistical information to determine if these objectives are being met. Freeway traffic management systems collect data for operating the facility that can also be used to support performance measurement. But traffic management systems are not the only source of data that can support performance measurement. Planning departments also collect data on system performance and leveraging these two data sources is highly desirable.
There are many possible users of freeway performance measures. The manager in charge of operating the freeway must judge the effectiveness of different control strategies. The traveler and freight carrier can better understand the condition of the system and alter their trips or, at least, anticipate congestion. Emergency responders can identify the best route to a site and reduce their response time. Transportation administrators, planners, and designers will take a longer-term view of the facility's performance and use the measures to determine how best to allocate the agency's resources. Consistent performance measures are fundamental to developing nationwide statistics that make sense. Consistent performance data would also benefit transportation researchers. Each of these users has different information needs that may be best addressed by different performance measures.
Objective: The objective of this research wasto develop a guide on the effective use of freeway performance measures in operating the system and in meeting the information needs of a large spectrum of potential local, regional, and national users.
Tasks: The project scope entailed the following tasks. (1) Describe potential uses of freeway performance measures and list the performance measures that are likely to be most appropriate for each use. In addition to operating the freeway, uses could include transportation planning, programming, and design; land use planning; air quality conformity; emergency response; evaluation of the national freeway system; information for travelers and freight carriers; and research. (2) Identify three to five metropolitan areas where exemplary use is being made of freeway performance measures in which to conduct benchmarking interviews during Task 3. Develop a plan for conducting the interviews that includes meeting with freeway operations managers and those responsible for other uses identified in Task 1. (3) Conduct benchmarking interviews based on the approved Task 2 plan. These interviews should identify best practices in the use of freeway performance measures. (4) Prepare a tentative set of appropriate performance measures, data requirements, and reporting techniques suitable for the uses identified in Task 1. The performance measures should support monitoring and evaluating (near term and long term) the performance of both individual freeways and the freeway system. Measures assessing the variability of performance should be included. Data needed to generate the performance measures must be described and potential sources of the data must be identified. Data reliability, level of aggregation, and quality control should be discussed, as should methods of aggregating data from different sources (particularly planning and traffic management systems). Identify methodologies for, and issues associated with, processing data to generate the performance measures. Discuss presentation methods for depicting performance measures and suggest standard reports for the different uses of the information. This discussion should consider the media for displaying the information, the format of the information, and reporting frequency. Long-term sustainability by a transportation agency should be considered throughout this task. (5) Prepare an interim report on the information developed in Tasks 1 through 4, including an annotated outline of the guide. The organization of the guide should be appropriate for the uses identified in Task 1 and include an executive summary. The report should also include an updated, detailed work plan for the remaining tasks. (6) Validate the information developed in Task 4 by presenting it to users of freeway performance information in several geographical areas, including at least one area that has limited experience with freeway operations. (7) Develop the guide based on the approved outline. The guide should be simple and practical and provide specific directions on how a transportation agency can generate and use freeway performance measures effectively. (8) Submit a final report that documents the entire research effort and includes the Task 7 guide as a stand-alone document.
Status: The project is complete.
Product Availability: The results of the project have been summarized in NCHRP RRD 312, and the final report is available as NCHRP Web-Only Document 97.