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Congestion Report 2020

At a glance

This is the second issue of a planned regular series that uses vehicle telematics data to provide measures of traffic congestion for freight vehicles on 53 selected routes across Australia’s five mainland state capital cities—Sydney, Melbourne, Brisbane, Adelaide and Perth over 2020.

The selected routes comprise the major motorways, highways and arterial roads within each city that service both passenger and freight vehicles. The data have been used to provide estimates of congestion based on how much longer journeys take (compared to a baseline of free running or uncongested conditions), and uncertainty in travel times (by measuring the variability of trips across each route over the year).

Comparing traffic congestion measures in 2020 with those of 2019 (BITRE 2021a), this report identifies several notable features across the selected urban routes:

  • Freight vehicle congestion decreased across all five mainland Australian capital cities in 2020 due to lower commuter activity on roads, particularly in peak periods, as a result of COVID-19 lockdowns.

  • Whilst peak period travel times were less pronounced in 2020 across all cities, this effect was more significant in Sydney and Melbourne, because those cities had larger pre-COVID-19 traffic peaks and experienced longer lockdowns (particularly in Melbourne) – in many cases traffic peaks in Melbourne disappeared entirely.

  • Morning peaks reduced by a greater extent than afternoon peaks, particularly in Sydney. This may be because commuting trips related to school student movements (most afternoon peaks are between 3-5 pm) returned earlier and are less flexible than commuting to work.

  • In Brisbane, peaks in uncertainty decreased more than peaks in travel times, but overall uncertainty mildly increased.

  • Perth and Adelaide showed less change between 2019 and 2020 overall than the eastern state capitals. These cities also experienced fewer or no COVID-related lockdowns.

  • Most routes exhibited a sharp decrease in congestion in April 2020 and a gradual, but incomplete return to pre-COVID-19 conditions by November 2020.

  • The unexplained ‘third peak’ noted on many surface routes in 2019 is usually still present.

This paper, the second of a planned regular series, tracks congestion of selected routes from across Australia’s major cities by estimating travel times based on observed speeds of freight vehicles. This report covers calendar year 2020.

The paper presents two ‘congestion’ measures for each route.

  • The first is the Mean Excess Time Ratio (METR) which reflects the how much the average expected travel time across the day exceeds the best (lowest) expected travel time. These best times are usually in the early morning hours, when network traffic volumes are lowest, and are assumed to be close to free running conditions.

  • The second is the Mean Excess Uncertainty Ratio (MEUR) which reflects how much the average uncertainty – measured as the breadth of the interquartile range, or the middle 50 per cent of trips – exceeds the lowest observed uncertainty.

These measures are only indicators of congestion and may be prone to ‘noise’ especially for routes or times of day (such as the early morning) with relatively sparse data. They also do not distinguish between a peak that lasts one hour and a peak that spreads over several.