Are the Main St Traffic Counts Really Accurate?

02 May 2019

Mr MORRIS (Mornington) (17:17): (541) I raise a matter for the Minister for Roads, and the action I am seeking from the minister is that she direct VicRoads to undertake an analysis of the traffic signal detector counts for the intersection of the Nepean Highway and Main Street, Mornington, recorded in January 2016, January 2018 and May 2018 and provide a breakdown of the number of vehicles entering Main Street from Mornington-Tyabb Road, entering Main Street from the Nepean Highway southbound carriageway, entering Main Street from the Nepean Highway northbound carriageway, exiting Main Street into Mornington-Tyabb Road, exiting Main Street onto the Nepean Highway southbound carriageway and exiting Main Street onto the Nepean Highway northbound carriageway.

In response to a constituency question lodged on 23 May last year the then Minister for Roads and Road Safety responded that VicRoads had undertaken traffic counts using traffic signal detectors at that intersection in January 2016, January 2018 and May 2018 and that the two-way average traffic volume in Main Street was 18 400 vehicles, 18 000 vehicles and 17 300 vehicles per day respectively.

There is a webpage on the VicRoads website titled ‘How traffic signals work’, which I accessed earlier today. That page indicates that traffic signals in Victoria have detectors in each lane at the stop line of every intersection. It goes on to say that you can see the outline of the rectangular loops at most intersections.

The detectors allow the system to collect a range of information, including the number of vehicles waiting, the number of vehicles using the intersection, what movements need a green signal and how long the green signal should be. It appears that these are the detectors that provided the data for the former minister’s response last year.

While I have no difficulty with the information provided, there is an issue that needs to be resolved, and that is how those elements of the intersection that do not contain a stop line are handled. It would appear that they may not be considered as part of that particular traffic light system.

In this case the intersection access from Main Street to the northbound lane of the Nepean Highway and the access to Main Street from the northbound carriageway of the Nepean Highway do not contain stop lines; they contain slip lanes only.

In the absence of stop lines it would appear that vehicles accessing Main Street and exiting Main Street through those slip lanes may not be counted under this system, so the provision of an analysis in the manner that I am requesting the minister have undertaken will allow reconciliation between the total number of vehicles recorded as using the intersection and an indication of the numbers using each of the other access and egress points.