Nelson/Tasman Speed Management Plan Economic Assessment

ViaStrada was commissioned to assess and report on the economic benefits of four urban and four rural options for the proposed Nelson/Tasman Regional Speed Management Plan. This was to inform deliberations by the local Land Transport Committee.

Using road section and speed data from MegaMaps and the Client’s GIS dataset, ViaStrada assessed the relative changes in crash casualties, travel times, vehicle operating costs, and emissions to derive benefit/cost ratios for each option, as well as identifying other intangible benefits (particularly for urban proposals).

While most of the rural road options demonstrated very good BCRs, the urban options were not able to. However, it was noted that in the urban area there are likely to be other benefits from speed management that are more difficult to accurately quantify, including health benefits from active mode shift, improved amenity, and reductions in air pollution and noise. There are also limitations to the assessment method due to likely variations in traffic congestion and delays at intersections.

A follow-up task provided an economic assessment on four specific sections of rural roads, all of which are currently at 100 km/h but proposed to be changed to 80 km/h. All routes demonstrated very good BCRs for these speed reductions. ViaStrada was able to produce this targeted information at short notice to enable it to be presented promptly to elected members.