New thinking for multi-modal corridors

Most transport corridors in urban areas are multimodal in that they carry a mix of public transport, private transport and freight vehicles as well as being important walking and cycling links. Yet, most transport key performance indicators look only at the performance of a specific mode, for example vehicle volumes, car travel time surveys or public transport patronage in their reports whilst the performance of the corridor as such is not measured. A recent pilot study in Auckland, New Zealand, sought to develop a performance indicator that would include and combine modes of transport to allow an improved understanding of the operation of multi-modal arterial corridors. This paper summarises the process and outcomes of work undertaken by the Auckland Regional Transport Authority and Beca to further improve on an existing Austroads performance indicator to create an improved and more flexible corridor performance indicator. The goal was to identify throughput and delay, which may differ by mode type, in a manner that would better inform decisions on how to manage the competing demands placed on arterial road space. The result of this work led to the development of a new “Car Equivalent Utilisation” (CEU) indicator, which can assess the efficiency of a corridor more directly then previous Austroads indicators. It does this by looking at “person” speed and throughput of a corridor by mode type, and comparing it to a set benchmark for a lane of general traffic. The new indicator was based on the Austroads Productivity: Speed and Flow indicator. Like the original Austroads it uses a benchmark for both speed and volume, the primary difference being that vehicle occupancy is taken into consideration such that the “flow” is a measure of people, rather than private vehicles. Using this new formula the pilot study found it possible to demonstrate the operation of the corridor by both public and private transport modes, and how changes to public and private transport influenced the results for each mode and the performance of the corridor as a whole. The results of the pilot study were such that it was possible to analyse the available data and identify dwell times for public transport (boarding and alighting times) as the single biggest constraint on the overall efficiency of the studied corridor. Using a sensitivity test with the CEU indicator, it was possible to demonstrate how reducing public transport delay to match that of private vehicles would significantly improve the overall efficiency of the corridor. The project did not attempt to study freight. The focus was primarily on road corridors; however the theory was extended to include possible comparisons with passenger rail. The indicator and its development is provided to ATRF with the intention of promoting discussion as to its usefulness and potential for further development.