Dilemma and option zones, the problem and countermeasures-characteristics of zones, and a new strategy of signal control for minimizing zones

The paper presents the characteristics of dilemma zone and option zone, where a driver can either stop or legally pass through the intersection, revealed by the data analyses on vehicle behaviour and the existing serious problems on using the constant clearance intervals and, as a countermeasure, a new strategy of signal control for minimizing dilemma and option zones.