Kingston’s yellow lights are not consistent and very random. To say our yellow lights meet the provincial guidelines of 3-5 seconds is not the safest approach. Each intersection has a set of variables, slope, visibility, road side distractions, width etc… Each intersection should have a unique yellow light time based on these, most all cases show that it falls .5 – 1 second over the provincial minimum. This is OK and this assessment of each intersection is encouraged. It’s all about ensuring the ‘dilemma’ zone is in the correct spot.
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Only a traffic engineer can calculate the appropriate yellow time ensuring we have the best ‘dilemma’ zone for each intersection helping us all stop safe. They can do this best using the posted speed or the 85th percentile approach speed , whichever is greater as well as a variety of other factors such as intersection width, weather, demographics of the intersection, pavement type/quality, viability etc…. Provincial guidelines specify the minimums, and should be increased as necessary, based on professional engineering judgment, to fit site conditions at any particular intersection.
Post time: Jun-07-2017