About VLimits 3.0VLimits 3.0 is an expert system which has been developed as a tool to assist practitioners in determining appropriate speed limits. It aims to reduce the degree of subjectivity associated with the evaluation of speed environments. In Victoria, the process for the determination of speed limits is structured around the following criteria:
- road characteristics
- extent and nature of the abutting development
- road users, their movements and the number of potential conflicts between road users
- crash history and
- seasonal factors.
The process is detailed in 'Speed Zoning Guidelines', Chapter 7 of the VicRoads Traffic Engineering Manual, Volume 1 (the Guidelines). Vlimits 3.0 suggests a speed limit value likely to be determined by a group of expert practitioners based on the road and traffic factors outlined in the Guidelines.
It is important to note that Vlimits 3.0 is only a tool to facilitate the implementation of the principles outlined in the Guidelines. It does not determine the speed limits.
Adjustments to the outputs from Vlimits 3.0 may need to be made in consideration of the local issues and site specific conditions. These advisory factors are listed at the end of the speed limit review process.
Vlimits 3.0 takes the user step by step through a series of questions relating to the road environment factors. The expert system logic used in this application dictates, that it will not ask the same series of questions in each case. Response to one question determines the next. Some factors, such as abutting development, are requested in all cases, while others like median width or presence of right turn lanes are requested only where they affect the suggested speed limit.
The Additional Information screens placed throughout Vlimits 3.0 provide further facts and advice on each factor covered by the screens.
For more information on speed zoning process please refer to the Guidelines or seek advice from VicRoads (refer to the 'Contact' tab for contact details).