BASIC TESTS TO SELECT SNOW–REMOVAL VEHICLES AND TO DETERMINE HOW SNOW PILES AFFECT PASSING VEHICLES, TOWARD THE ADOPTION OF ROUNDABOUTS IN JAPAN

摘要

Roundabouts are recognized as safe grade intersections, and they have been actively adopted in the U.S. and Europe. Engineering guidelines have been developed for roundabouts in Japan, and the first roundabout here was built to replace a signalized intersection. The time is ripe for Japan to introduce roundabouts to its road systems. However, because snowy cold regions account for about 60% of Japan's land area, it is necessary to address various issues related to winter maintenance before introducing roundabouts to these cold regions. Few studies have addressed techniques for managing and maintaining roundabouts in winter. Thus, for the purpose of collecting data that can be referred to for roundabout installation in snowy cold regions, tests were conducted at a simulated roundabout whose circulating roadway had an outside diameter of 26 m. In the tests, snow removal vehicles were used for measuring the vehicular swept paths, and the minimum central island diameter that allowed the vehicles to remove snow was identified for each type of vehicle. Additionally, simulated snow piles were used for investigating how snow piles from snowfall or snow removal affect driving behavior. This paper outlines these tests and their results.