There are various types of vehicles, and each has a different swept path. These include passenger cars, buses, commercial vehicles and emergency service vehicles. The size and shape of a vehicle determine its swept path. For example, a truck has a longer wheelbase than a passenger car and requires a wider turning radius. The design vehicle for each site will depend on the nature of the site and regulatory standards. Typical design vehicles for residential sites include B99 and B85 passenger cars which represent the 99th and 85th percentile vehicles in terms of size, respectively.
Vehicle clearances are applied to maintain a margin for error and realistic assessment. Generally, a 300mm clearance is applied to the body of the vehicle in slower speed environments such as car parking areas. Vehicle dimensions, design standards and clearances for car parking areas are provided in the Australian Standards, specifically AS/NZS 2890.1.
Why Are Swept Path Assessments Important?
Swept path assessments are important for several reasons. Firstly, they help to ensure the safety of road users. By identifying potential conflicts between vehicles, pedestrians, and cyclists, road designers can make adjustments to the road layout or traffic management systems to minimise the risk of accidents. For example, a swept path assessment may identify that a roundabout is too small to accommodate a service vehicle without encroaching onto adjacent lanes. In this case, the roundabout may be redesigned to make it wider or to provide mountable kerbs.
Finally, swept path assessments are essential for the efficient use of space. By identifying the amount of space required for vehicle manoeuvring, the site layout and car parking can be optimised to maximise efficiency and usable space.
In conclusion, vehicle swept path assessments are an essential aspect of road design and traffic management. By simulating the movement of vehicles through the road network, designers can identify potential conflicts and make adjustments to improve safety, accommodate larger vehicles, and optimise traffic flow. With the continued evolution of vehicle technology and the growing demand for sustainable transport, swept path assessments will continue to play a critical role in the design and management of our road infrastructure.