This paper describes how the opening of the Shin-Meishin Expressway in Japan to traffic on February 23, 2008, created a new route on the expresswaynetwork connecting Osaka and Nagoya, in addition to the existing Meishin route. It became possible for drivers to select a preferable route, and significant improvement was anticipated in reliability of travel time on thenetwork. As things stand at present, however, the only section that provides alternative routes is east of the Kusatsu Junction. Expressway travel west of the Kusatsu Junction depends on the single route of the Meishin Expressway, except for the double-route section with the Keiji Bypass. When traffic delays occur due to congestion resulting from traffic concentration in sections where route selection is not possible, or when congestion occurs because of traffic accidents or road works (hereafter referred to as incidents), then the travel time reliability is often significantly damaged. As a result, it becomes difficult to assure time reliability over the route as a whole. The formation of networks which will provide drivers withalternative routes is therefore an important issue for expressways. Previous researches have indicated that expressway sections with alternative routes show improved reliability in travel time, but there have not yet beenany empirical studies that focus on the substitution function when incidents occur. This paper seeks to evaluate the improvement in travel time reliability achieved by the formation of the expressway networks. Given that sufficient amounts of data have not yet been accumulated since the Shin-Meishin Expressway was opened to traffic, travel time reliability indicatorswere calculated on a section of the expressway (Section A and C) that wasexpanded to a double route with the full opening of the Keiji Bypass in August 2003, and on an adjoining single-route section (Section B). The focus was placed on traffic dispersion over the double-route section and incident avoidance.
Samenvatting