¥Here
are the prior best practices that were based on fully vetted empirical
research.
¥
" "The primary measure of effectiveness for
the yellow interval is the percent of vehicles entering the intersection after the termination of
the yellow indication; that is, during the red following the yellow." ...... "When the percent of vehicles that are last through the intersection which enter on
red exceeds that which is locally acceptable
(many agencies use a value of one to three percent), the yellow interval should be lengthened until
the percentage conforms to local standards."
¥
¥["Determining Vehicle Change Intervals - A Proposed
Recommended Practice", Institute of Transportation Engineers,
Washington, D.C., 1985, page 6] The local standard was defined as 1 to
3 percent non complianceÉ] (to meet 97th to 99th percentile of
trafficÕs need)
¥