The National Academies Press

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From page 5... ... 5C h a p t e r 2 Chapter 2 of this report describes the literature on measurement, value, and use of travel time reliability in planning. While interest in travel time reliability is growing, few transportation agencies are actively using reliability performance measures within their planning and programming processes. Read the entire page →
From page 6... ... 6Small et al. observed that travelers experienced better service quality in express lanes because of travel time savings and travel time reliability (13) Read the entire page →
From page 7... ... 7Sirivadidurage et al. of the University of Leeds forecasted day-to-day variability in travel time on the UK motorway network (19) Read the entire page →
From page 8... ... 8Methodologies for calculating lateness and variability for different modes are established in the TAG. A qualitative score is reported for reliability for instances when quantitative measures cannot be calculated. Read the entire page →
From page 9... ... 9response times for emergency service vehicles and the HELP (Highway Emergency Local Help) program. Read the entire page →
From page 10... ... 10 have low buffer indices because the buffer index is a measure of day-to-day differences. MWCOG staff concluded that use of a median-based buffer index and failure rate is preferable to avoid underestimating unreliability. Read the entire page →
From page 11... ... 11 Figure 2.2. Example map of buffer-time index: Workday a.m. Read the entire page →
From page 12... ... 12 vehicle platform can be used for analysis of performance measures. It will generate data that provides metrics to measure the effectiveness of system operation, including travel time, stops, delays, and travel reliability; condition metrics, including indicators of pavement traction, pavement roughness, precipitation, visibility, and air quality; and demand metrics, such as vehicle counts. Read the entire page →
From page 13... ... 13 2. Management and operations considerations within the context of the ongoing regional transportation planning and investment process; and 3. Read the entire page →
From page 14... ... 14 separate capital, operating, and maintenance and staff budgets. The corridor plans of the Washington State Department of Transportation (DOT) Read the entire page →
From page 15... ... 15 an objective allocation of resources, to prioritize regional investments in management and operations, to increase accountability, to engage the community, and to expand the focus of the metro politan transportation plan to include both short- and long-range operations needs (31) Read the entire page →
From page 16... ... 16 alter the course of freight performance measure development for the agency: 1. Turnaround time for information; 2. Read the entire page →
From page 18... ... 18 • The time interval for aggregating speed and volume from sections of roadway should be shorter than the travel time under free-flow conditions. • The optimum data collection period for the reliability measurement was reported as a six-week period using data collected at intervals of 5 min or less. Read the entire page →
From page 19... ... 19 Hanshin Expressway is an urban toll expressway network that stretches from Osaka to Kobe. For this study, travel time reliability indices were calculated for five radial routes that are connected to the downtown loop route in Osaka City. Read the entire page →
From page 20... ... 20 develop concise guidance for transportation professionals to forecast and predict reliability performance measures. Several SHRP 2 projects are developing analytic methods for estimating reliability directly, from a variety of resolution scales, from sketch planning to microscopic simulation: • SHRP 2 L03 developed statistically derived reliability equations based on empirical data. Read the entire page →
From page 21... ... 21 travel-demand models used to predict future travel conditions only estimate recurring congestion and do not include nonrecurring sources of congestion (e.g., incidents, weather) Read the entire page →
From page 22... ... 22 Many transportation agencies use benefit-cost analysis to capture the expected benefits of transportation investments. Benefit-cost analysis assesses the user and agency benefits of projects and programs in comparison to their costs. Read the entire page →
From page 23... ... 23 stated-preference survey data for long-distance car travel (three hours) in New Zealand, Hensher calculated the value of travel time savings for free flow travel time to be NZ$3.60 (U.S. Read the entire page →
From page 24... ... 24 speeds with traffic volume and roadway inventory databases to measure multiple facets of traveler mobility, including reliability. As agencies become more familiar working with travel time data sources, they can turn to available procedures to calculate reliability measures. Read the entire page →
From page 25... ... 25 construct transportation improvement programs that include management and operations projects to help fulfill federal requirements. • Reliability can be monetized. Read the entire page →
From page 26... ... 26 30. Zhang, L., and K Read the entire page →

From page 5...

... 5C h a p t e r 2 Chapter 2 of this report describes the literature on measurement, value, and use of travel time reliability in planning. While interest in travel time reliability is growing, few transportation agencies are actively using reliability performance measures within their planning and programming processes.