Improving freeway capacity analysis

07 December 2020

Austroads has released a research report which reviews and evaluates established and emerging methodologies in freeway capacity analysis.

Richard Delplace, Austroads Program Manager Transport Network Operations says freeway capacity analysis is an important process undertaken at the planning stage of freeway construction or upgrade projects to determine the number of lanes for mainlines and entry or exit ramps, as well as for anticipating levels of service along the route.

"Freeway capacity analysis is also important for managing freeway operations to ensure peak flows are kept below capacity, thereby reducing the probability of flow breakdown,” said Richard.

Austroads Guide to Traffic Management and Guide to Smart Motorways primarily reference the US Highway Capacity Manual in providing freeway capacity analysis guidance and freeway design capacities.

Recently, however, researchers, practitioners and road operators have investigated the probability of flow breakdown and revised capacity values to provide more sustainable parameters applicable to actual operational conditions, particularly for critical segments such as entry ramp merges, weaving areas, lane drops and exit ramp diverges.

Following a comparative analysis of the various freeway capacity analysis methodologies used by Austroads member agencies, the project recommends practitioners consider adopting the maximum sustainable flow rate and the flow rate at maximum productivity methodologies which are currently used by Victoria Department of Transport.

Download: Improved Traffic Management Guidance: Freeway Capacity Analysis,

Join us for a webinar on Tuesday 16 March 2021 from 1:00–2:00 pm AEDT. ARRB Senior Technology Leader, Paul Bennett will present the research and findings outlined in the report, including consultations with practitioners from across Australia and New Zealand, a comparative study of different capacity analysis methodologies, and the recommendations made for updating Austroads freeway capacity analysis guidance.

No charge but registration is essential. Can’t make the live session? Register and we’ll send you a link to the recording.

Register now! 




Source:  Austroads -

Date of Original:  30 November 2020

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