Friday Seminar - Ilgin Guler on Strategies for Sharing Bottleneck Capacity among Buses and Cars

let photo speak...

Tomorrow's TRANSOC Friday Seminar features Ph.D. candidate Ilgin Guler presenting, "Strategies for Sharing Bottleneck Capacity among Buses and Cars."

Buses that operate in mixed traffic can be impeded by car congestion, leading to unreliable and slow bus service. Conversely, buses that frequently stop to serve passengers can interfere with the movement of cars. To address these issues, exclusive bus lanes have often been used to segregate buses from other traffic. These exclusive bus lanes provide a means for buses to bypass car queues, thereby increasing bus speed and potentially decreasing the total person hours travelled on a network. In urban settings exclusive bus lanes are typically deployed by converting an existing general purpose lane to bus use only. However, in cases where bus flow is low, these lane conversions can increase the queuing and delays to cars. The problem is particularly acute at roadways bottlenecks, since cars now discharge from one less lane, even when the bus lane is unoccupied.

This research examines strategies for judiciously inserting cars between buses in ways that minimize the losses in a bottleneck’s car carrying capacity when bus demand is low. The idea entails sharing lanes among buses and cars in the vicinities of critical bottlenecks; and to have these shared lanes augment exclusive bus lanes that are deployed elsewhere throughout the network. The specific type of sharing strategy to be used near any given bottleneck would depend upon its operating conditions. In all cases the goal is to prioritize bus travel while minimizing the additional delays that this prioritization imparts to cars. Analysis unveils the ranges of bus demands for which the shared‑lane strategies are superior to ordinary lane conversions. We find that the shared-lane strategies have merit in many instances. Implementing these strategies for a real-world case study in Amman, Jordan produces promising outcomes: simulation analysis indicates that the delay savings to cars brought by the lane–sharing strategies are considerable. The proposed ideas can help increase the political acceptability of bus priority systems and promote public transportation in cities of various sizes.

The Seminar will be from 4-5pm in 406 Davis Hall. There will be no cookie hour precedding it this week, so you'll need to sort out your sugar fix some other way.