Pre-timed Actuated
Type of Operation Isolated Coordinated Semi-Actuated Fully-Actuated Coordinated
Fixed Cycle Length Yes Yes No No Yes
Conditions Where Applicable Where detection is not available Where traffic is consistent, closely spaced intersections, and where cross street is consistent Where defaulting to one movement is desirable, major road is posted 40 mph Arterial where traffic is heavy and adjacent intersections are nearby
Example Application Work Zones Central business districts, interchanges Highway operations Locations without nearby signals; rural, high speed locations; intersection of two arterials Suburban arterial
Key Benefit Temporary application keeps signals operational Predictable operations, lowest cost of equipment and maintenance Lower cost for highway maintenance Responsive to changing traffic patterns, efficient allocation of green time, reduced delay and improved safety Lower arterial delay, potential reduction in delay for the system, depending on the settings