This paper presents research on a real-time bus-holding control strategy that minimizes passenger waiting time. This bus-holding strategy forces buses to hold at stations for a while after a passenger exchange is finished. A mathematical model is proposed to determine the optimal holding time. Both onboard and on-station passenger waiting times have been taken into account. Given the real-time nature of the problem, a heuristic method based on gradient descent algorithms was developed. The proposed control strategy was evaluated by using data derived from a shuttle bus rapid transit (BRT) line in the city of Mashhad, Iran. The BRT line was simulated and calibrated by available empirical and real-time data from the automatic vehicle location and automatic passenger counting systems. The results indicate that the proposed bus-holding strategy reduces total passenger waiting time by 8.65%.

Unnecessary traffic delays and vehicle emissions have adverse effects on quality of life. To solve the traffic congestion problem in the U.S.A., mitigation or elimination of bottlenecks is a top priority. Agencies across the U.S.A. have deployed several congestion mitigation strategies, such as lane and shoulder width reduction, which aim to adding lanes without significantly altering the footprint of the freeway. A limited number of studies have evaluated the operational benefits of lane narrowing. Although the Highway Capacity Manual does account for lane and shoulder widths, the adjustments that it provides are outdated. The goal of this research was to develop analytical models, compatible with the Highway Capacity Manual methods, to account for lane and shoulder width narrowing, using field data from across the U.S.A. This paper presents a new free-flow speed regression model, which accounts for lane and shoulder widths, and capacity adjustment factors depending on the lane width.

The capacity of a freeway segment is a critical factor for planning, design, and operational analysis of freeway facilities. This research aimed to perform a comparison among well-known freeway capacity estimation methods in order to investigate their application, as well as their advantages and disadvantages. Single estimate capacity methods such as the Van Aerde method, and breakdown probability methods, such as the product limit method (PLM), the Highway Capacity Manual (HCM) method, and the sustainable flow index (SFI) method, were applied at six merge bottleneck locations in the Kansas City area. The results from all methods were compared and the advantages and the disadvantages of each method were discussed. The HCM results showed a significant variability in the estimated breakdown probability function and the resulting capacities. The HCM method was also found to be sensitive to the breakdown probability ratios as a single breakdown observation can significantly shift the fitted distribution and the corresponding capacity estimate. The PLM model provided the highest capacity estimates, followed by the Van Aerde model capacities. The Van Aerde capacities were also found to be closer to the average pre-breakdown flow rates. Finally, the PLM and the SFI method showed consistent performance in comparison to the remaining methods, and flexibility in being applied on different sites with various characteristics.

No abstract

No abstract