Requirements and procedures for employing simulation in ITS applications

The need to simulate a number of advanced ITS concepts prior to deployment necessitated development of high performance microscopic simulators for heuristic dynamic traffic assignment, freeway corridor diversion, driver information systems including variable message signs and vehicle guidance systems, real-time adaptive traffic control and other traffic management concepts. In spite of recent progress in developing sophisticated simulators for ITS applications their employment in real life projects requires substantial data collection, testing, validation and calibration. The latter is often ignored in practice where for convenience simulators are often used without sufficient validation and calibration, resulting in unreliable and/or inaccurate results. The objective of this paper is to demonstrate the issues and lessons learned in the employment of a sophisticated simulator for evaluating the effectiveness of adaptive ramp control in the Twin cities of Minneapolis and St. Paul, which is one of the earliest and most extensive worldwide (210 miles of freeway, 430 ramp meters).