Green wave for high capacity public transport services

Prioritising high capacity public transport services such as bus and Light Rail Vehicles (LRVs) offers the possibility of increasing the hourly customer throughput of on-street transport in big cities like Sydney, potentially reducing delays at high congestion points in Central Business Districts (CBDs). A key means of doing this is through implementation of Transit Signal Priority (TSP) systems.

This project introduces innovations to standard TSP approaches by developing an algorithm set that minimises the green extension and red reduction of the LRV or bus priority phase by calculating an optimum approach speed for the public transport vehicle. By speeding up or reducing the LRV approach speed, the priority signal phase is less while still giving priority to public transport with the advantage of reducing the potential stop time for private vehicles.

Participants

• Transport for NSW
• University of Technology Sydney

Project background

Prioritising high capacity public transport services such as bus and LRVs offers the possibility of increasing the hourly customer throughput of on-street transport in big cities like Sydney. It could also potentially reduce delays at high congestion points in a CBD. A key means of doing this is through implementation of TSP systems.

At a macroscopic level, average road traffic speeds — or variable speed networks influenced by congestion or vehicle numbers — are known to be heavily influenced by the speed of the public transport or fixed/scheduled speed network. When public transport speeds are faster, more people are attracted to them and this potentially lifts variable speed network performance by reducing private vehicle numbers.

Mesoscopic traffic control measures such as TSP systems are a critical component in realising these macroscopic system goals of lifting the performance of both fixed and variable speed networks.

This project introduces innovations to standard TSP approaches by developing an algorithm set to be potentially applied to the signalling system in NSW. This would minimise the green extension and red reduction of the LRV or bus priority phase by calculating an optimum approach speed for the public transport vehicle. The algorithm could also be applied to TSP for buses.

By speeding up or reducing the LRV approach speed, the priority signal phase is less while still giving priority to public transport with the advantage of reducing the potential stop-time for private vehicles.

Project objectives

The general objective is to increase the throughput of people or road network customers at key intersections. The aim is to achieve higher capacity public transport services, able to increase hourly throughputs by a factor of 4 to 5 without significantly penalising lower-capacity private motor vehicle users. This will result in higher throughput or capacity with reduced delays, benefiting both public transport and private vehicle road users.

The project has two distinct parts, aiming to:

1. Produce a set of algorithms that could be incorporated into a more innovative signalling system to optimise high capacity public transport signal priority.
2. Work with Transport for NSW and agencies within its transport cluster to select a set of intersections along a light rail route to test the algorithms, and provide feedback on their performance with the aim of incorporating them into a live road traffic signalling system. Where appropriate, adapt algorithms to accommodate restrictions presented by the on-street signalling hardware.

Please note

Ongoing, this page will be a living record of this project. As it continues, matures, hits milestones, etc., we’ll add information, links, images, interviews and more. Watch this space!