Travel speed is a critical piece of information for many applications. It is a measure that is often used to calculate the performance of the nation’s highway networks. In 2011, the Kentucky Transportation Cabinet (KYTC), in collaboration with the Kentucky Transportation Center (KTC) at University of Kentucky, purchased speed data for 2010 and 2011 from NAVTEQ (now HERE). In 2013, speed data for the year 2012 were acquired from the same vendor. The specific data items included: * 2010 Analytical Traffic Pattern (ATP) * 2010 Traffic Pattern (TP) * 2011 Link-Referenced ATP * 2012 Link-Referenced ATP The main objectives of this research were to: * Evaluate the private sector speed data with regard to its use in generating travel time based performance measures * Create a mechanism to integrate this speed data with networks maintained by KYTC and Kentucky Metropolitan Planning Organizations (MPOs) to facilitate congestion management and travel model improvement * Generate performance measures including travel time index, planning time index, buffer index, annual hours of delay, and percentage travel under congested conditions Evaluation of the data indicated that link-referenced ATP data offered the best value for a wide range of applications. It can be used to generate performance measures on many Kentucky roadways, including many minor arterial and collectors that are not typically included in the TMC network. Link-referenced ATP had finer spatial resolution, which allowed for the identification of bottlenecks on longer corridors. The calibration and validation of travel demand models and simulation models may also benefit from the data because they reflected measured and unedited speeds across different times of day. Among the three types of data evaluated, the link-referenced ATP data should be the first choice when future purchases of private sector speed data are made. The analyses performed as part of this study demonstrated the robustness of the link-reference ATP data, and these findings will support KYTC’s and MPOs’ needs for performance tracking. Since probe vehicle data were not available on all segments for all time intervals, private sector speed data remained sparse on many roadways, especially low volume rural roads. Nevertheless, probe vehicle sample size and coverage has improved over recent years. For segments with adequate sample coverage, performance measures were generally reliable. When sample size is a concern, the research team suggests that data from other sources (such as Bluetooth, radar, and others) supplement private sector speed data. A range of congestion and reliability performance measures were generated from these data after they had been conflated with the KYTC’s highway inventory network. Results were sent to KYTC and MPO stakeholders in the form of geodatabases. Other applications can benefit from these data, including: the calibration and validation of simulation models, travel demand models, and air quality analyses. (Author/publisher)
Samenvatting