Monday, 22 August 2016
Austroads has published an Excel tool and user guide, to help practitioners undertake a quick economic evaluation of small intersection projects including: give-ways/stops, roundabouts and traffic signals.
The tool can be used by practitioners working with basic traffic data to estimate road user cost impacts, primarily delay and fuel costs, as well as crash costs.
The Small Intersection Evaluation (SIE) Tool does not aim to replicate sophisticated intersection analysis software or the packages developed by various jurisdictions to undertake detailed analysis of large intersection projects. Rather, the objective is to facilitate the economic evaluation of a number of small intersection projects which could provide an indication of the most promising projects which can then be subject to further detailed analysis thereafter.
The report, Development of the Traffic Impact Estimation Tool for Small Intersection Projects, describes the development of the tool.
The report includes the tool's overall design, methodology and data requirements (base case and project case) for the estimation of traffic impacts at signed intersections, roundabouts and signalised intersections. The estimation of crash costs across intersection types is also presented, including appropriate crash rates and crash modification factors (CMFs) incorporated into the SIE Tool. Results of the intersection evaluation in terms of economic decision rules, i.e. net present value (NPV) and benefit cost ratio (BCR) are provided.
The report also sets out the process used to review and test the SIE Tool against available case studies. This includes feedback received from jurisdictions on testing the tool and the appropriate adjustments made to the tool in response to the comments. Finally, it must be noted that the coefficients used to estimate delay and vehicle operating costs in the SIE Tool are updated periodically via a separate, off-line process as new unit values (e.g. travel time and fuel costs) become available.
The SIE Tool and the User Guide can be downloaded from www.onlinepublications.austroads.com.au/items/AP-R523-16.