Analysing benefit realisation of major highway upgrade

Connected Vehicle data helped to perform an analysis of the benefits of upgrading Northern Road.

The Northern Road is located in Western Sydney and connects Penrith, Liverpool, Parramatta, and the eastern suburbs of Sydney. Transport for New South Wales (TfNSW) wanted to investigate five key intersections between South Penrith and Narellan after upgrading parts of the Northern Road from two lanes to four.

Specifically, TfNSW wanted to analyse speeds, trips and vehicle types to identify changes in driver behaviour before and after the upgrades, looking at the past four years - 2020, 2021, 2022, and 2024. They expected to see higher speeds, less travel time and an increase in trucks due to the wider road. They also wanted to understand how this changed across AM peak and PM peak.

To help their investigation, Compass built a dashboard identifying trip counts and growth, travel times, and average speed across the five key intersections.

The dashboard showed that the Northern Road usage had significantly increased and that in 2024, drivers used the Northern Road 7 times more than in 2020. Data also revealed that trips on the Northern Road were more commonly made in the AM peak period.

In 2024, during peak hours, drivers typically used sections of the Northern Road north of Cranebrook, south of Kemps Creek and south of Luddenham - an increase since 2020. On the heatmap image below, this is indicated by red showing high trip counts and driver usage, while green indicates less trips and use.

Across each of the five intersections of interest, northbound traffic saw an increase in trips and travel time in the AM peak. Most intersections saw speed reductions immediately before or after the approach, except for Littlefields Rd, where speed increased despite increased travel time. Similar patterns occurred during the PM peak but with more pronounced effects. For instance, at Glenmore Parkway, the average speed was reduced by 50 km/h before the intersection at the PM peak versus 37 km/h in the AM peak.

Image: Average speed and median travel time for northbound traffic

Southbound traffic across the five intersections saw the opposite. While trip counts increased, speed and travel times were better maintained compared to northbound traffic. Speed typically decreased approaching intersections, for example, Glenmore Parkway only experienced a 30 km/h drop in average speed, but often improved before or after the approach to the intersections. The PM peak was similar but had a limited speed increase before and after passing through the intersection, contrasting with AM patterns.

This dashboard helped TfNSW assess the benefit realisation of the Northern Road lane upgrades on intersection performance and driver behaviour across four years. The insights gained from this analysis can help inform future infrastructure planning and business case development of similar types of projects.