Quantitative method of effects of snow removal deployment
Traffic delay costs borne by users are added to winter maintenance costs, and the totals for various combinations of these are compared to determine the most cost-effective combination.
Method to improve efficiency of salting by setting temperature based rating rates.
A uniform salting rate has been used throughout the Hokuriku Region of Japan, even though air temperatures there vary from location to location. Field surveys revealed that some road sections were over-salted. We came up with a method of basing the salting rate on the air temperature. Doing this achieved a 23% reduction in salting costs over the previous winter?a winter when a uniform salting rate was used for the entire region. Despite this reduction, no dangerous road conditions occurred.
Effects maintaining salinity by the ditche on shoulders.
Snowmelt water that seeps from the roadside onto the road reduces the salinity on the carriageway surface. We installed ditches at the road shoulder to prevent intruding water from decreasing the salinity on the road surface. At test installation sections, the salinity on the carriageway was higher after ditch installation than before ditch installation. This proved the effectiveness of the ditches.
The development of a tool for determining the uphill road sections that vehicles have trouble climbing
In a single year in Hokuriku, there were 160 instances of vehicles being unable to climb uphill road sections in winter. We surveyed such cases and made a database of the following for each such incident: the winter maintenance work, the occurrence location, the occurrence date and time and the time of resolution, the weather, the state of the road at the location, and the vehicle characteristics. Based on the database and maps, we made a tool that identifies the uphill locations that vehicles have trouble climbing in winter.
We made a database of such locations and mapped them. Mapping was done by using a GSI map from the Geospatial Information Authority of Japan, and we built a system that allows occurrence locations to be visually clarified. The system was found to be effective at determining uphill road locations that vehicles are at risk of being unable to climb and at identifying the conditions under which such inability occurs.