Vehicle modelling software utilised to prepare vehicle swept paths is an essential tool to ensure a vehicle of a specific size can undertake the required manoeuvres at any given location, whilst ensuring the safety of all road users and optimization of trafficable space. This has flow on effects and contributes to the surrounding road network operating holistically in an efficient and safe manner.
In the evening peak-hour period, a mid-sized truck was attempting to turn left from the minor road into the major road at a heavily congested T-intersection. It became quickly apparent that it did not have sufficient space to make the turn in one manoeuvre even with the use of the opposing lane. I use the term ‘lane’ loosely here, but that’s a topic for another time. The attempted turn not only caused even more delays to all vehicle movements at this intersection – which was already moving at a speed between parked and crawling – but required intervening from people nearby to help control traffic and guide the driver as they performed multiple corrective manoeuvres. The turning manoeuvre was eventually completed but no doubt resulted in a significant delay for the surrounding road users.
So, what solutions can be presented for this scenario? Negating the socio-economic and political differences between Australia and Indonesia, traffic management solutions such as signage upstream can be installed to prevent vehicles of a certain size to enter the road. This however is only an administrative control (quite low on the hierarchy of risk controls) and should be installed only where the road geometry cannot be modified due to surrounding land use constraints. Conversely, for certain road sections where it can be altered, or when in the planning and design stages, specialised vehicle modelling software such as AutoTrack or AutoTurn can be very useful in determining the required geometry of the road.
As a Traffic Engineer at Amber, performing swept path assessments using AutoTrack is a common task undertaken which provides traffic engineering related insights and solutions to clients of various sectors of the wider industry. Typically, in my experience, they’re performed in the design stages in conjunction with the architect and other consultants, long before the development is built. In some scenarios, such as part of the renewable energy sector, key road intersections require upgrades to allow larger vehicles to satisfactorily make their turning movements. That is, without needing to go off-road and without the use of corrective manoeuvres. Depending on traffic volumes, a turn treatment such as a Basic Left Turn (BAL) or Basic Right Turn (BAR) may be designed and constructed which further increases the efficiency of the road. The following figure is an example of an upgraded intersection with the swept paths for the critical vehicle size overlayed on top, in this case a 26.0m long B-double. Modelling the paths of these vehicles ensures the intersection can be upgraded adequately to operate safely and efficiently for the road users.
