A Markov process based dilemma zone protection algorithm

Dilemma zone (DZ) is an area at high-speed signalized intersections, where drivers can neither cross safely nor stop comfortably at the yellow onset. The dilemma zone problem is a leading cause for crashes at high-speed signalized intersections and is therefore a pressing issue. This paper presents a novel Markov-chain-based dilemma zone protection algorithm that considers the number of vehicles caught in DZ as a Markov process. The new algorithm can predict the numbers of vehicles in DZ and determine the best time to end the green so as to reduce the number of vehicles caught in DZ per hour. The algorithm was compared to the traditional green extension system and the results showed that the new algorithm was superior.