Overview

RODEL is a tool for roundabout designers and practitioners which assists them to:

  • Improve design quality
  • Drastically reduce design time
  • Reduce land and service utility relocation costs
  • Rapidly explore many geometric options, especially with respect to safety
  • Derive the optimum layout within the conflicting constraints of cost, delay and safety
  • Conduct planning level studies to evaluate intersection alternatives

Rather than simply checking designs after they have been drawn, RODEL generates geometry prior to scheme drawing. This avoids the time consuming practice of repeatedly drawing layouts and checking performance.

RODEL is a powerful, accurate, and efficient tool designed to allow the practitioner to understand operational effects of different geometries and their impact on performance. The program provides accurate capacity and delay analysis data to assist a designer in finding a comprehensive solution for a given problem.

The History of Rodel

During a period from approximately 1974 to 1980, professor Rod Kimber, then Head of Junction Design at the Transportation Research Laboratory (TRL),conducted controlled test track experiments on 35 roundabout layouts and analyzed data from almost one million vehicles during 11,000 minutes of "at capacity operations" on 86 field roundabouts covering the full range of geometric and traffic conditions. The studies produced "Kimber's Equations," which are used to accurately estimate the capacity of roundabout entries based on six geometric parameters. The research evaluated 35 different geometric parameters, and determined that only six of them were logically independent and statistically valid for determining capacity. Using Kimber's Equations, RODEL is able to determine accurate capacity measurements for a given design.