Road Design

This guide has been developed to assist intersection designers and contains user information and a guide (covering the basis of turning templates and road hierarchy), design vehicle dimensions, and turning path templates.

When a long vehicle makes a low-speed turn at an intersection, the rear of the vehicle covers a wider area than the inside of the path of the front of the vehicle. This is known as low-speed off-tracking. The swept path is the road area covered by the outermost and innermost points of the vehicle making the low-speed turn. Since the road network consists of a hierarchy of roads with different functions, it is necessary to have a range of design vehicles in order to provide appropriate and safe access.

The templates can be downloaded from the links below:

• design vehicle dimensions and drawings in PNG and PDF formats [625 Kb zip file]
• turning templates in DWG (AutoCad 2010) and PDF formats [28 Mb zip file]

The design vehicles included in this document provide guidance to cover most normal intersection designs. The vehicle turning path templates are plots of the vehicle wheelpath and the path traced by other relevant points on the vehicle or load. They show the swept path envelope resulting from various angles of turn at a particular radius.

Edition 4.0 has been restructured with additional guidance on design vehicles versus checking vehicles, performance based standards, clearances between swept paths, software parameters and a new design vehicle for a passenger vehicle towing a trailer.

This fourth edition includes templates for:

Passenger vehicle (5.2 m)

• 6.3 m radius

Passenger vehicle towing trailer (17.6 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Service vehicle (8.8 m)

• 9 m radius, 5 km/h
• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Single unit truck/bus (12.5 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Long rigid bus (14.5 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Articulated bus (19 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Prime mover and semi-trailer (19 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Passenger vehicle (5.2 m) and a prime mover and semi-trailer (19 m)

• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

Prime mover and long semi-trailer (25 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

B-double (25 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

B-double (26 m)

• 12.5 m radius, 5 km/h
• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

B-triple (35.4 m)

• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

A-double (Type I road train) (36.2 m)

• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h

A-triple (Type II road train) (53.4 m)

• 15 m radius, 5 to 15 km/h
• 20 m radius, 15 to 20 km/h
• 30 m radius, 20 to 30 km/h.

Notes:

• The maximum length permitted for an A-double is 36.5 m, however the overall length of the vehicle combination is 36.2 m which reflects typical dimensions.
• The maximum length permitted for an A-triple is 53.5 m, however the overall length of the vehicle combination is 53.4 m which reflects typical dimensions.

Watch a recording of the webinar with Noel O’Callaghan and Malcolm Mak to learn about the new edition of the Guide.