New models for estimating negotiation radius, distance and speed values of through and turning vehicles at roundabouts were introduced in aaSIDRA version 2. The intersection negotiation parameters are important in determining geometric delays, fuel consumption, pollutant emission and operating cost values for traffic using roundabouts. The paper gives figures showing simplified constructions of vehicle paths for through, left-turning and right-turning vehicles. The method allows for path smoothing by drivers. The safe negotiation speed formula uses a side friction factor that is a function of vehicle mass. Graphs showing the side friction factor as a function of the vehicle mass, and negotiation speed as a function of the turn radius are presented. The negotiation radius, distance and speed values as a function of the roundabouts size, and graphs showing the sensitivity of geometric delay to roundabout size and approach and exit cruise speeds are presented.
AKÇELIK, R. (2002). Estimating Negotiation Radius, Distance and Speed for Vehicles using Roundabouts. Paper presented at the 24th Conference of Australian Institutes of Transport Research (CAITR 2002), University of New South Wales, Sydney, Australia, Dec 2002. Updated: 14 Oct 2004.