A comparative study of 5 signal timing control methods indicated that the most efficient method of signal control is the micrioprocessor which would allow an intersection to operate under actuated control during certain periods of the day and under predetermined timing patterns during other periods. The 5 signal timing methods considered were: Traffic Engineering Method, FHWA Design Manual Method, Fully Actuated Operation Method, Microprocessor with lagging Left-Turn Method, and Microprocessor with Leading Left-Turn Method. The "before" and "after" evaluation of these methods was made by pairing them in a series of six comparisons using time-lapse photography to supply vehicle data. The site selected for application of these comparisons was the Diamond Interchange of Interstate 95 Golfair Boulevard in Jacksonville, Florida. The study procedure is appropriate for signal timing studies made at: a diamond interchange, other interchange configurations with a ramp terminal and nearby signalized intersections, and a 2-way major street intersected by one or more one-way street pairs.