More flashing yellow left-turn signals coming to St. Charles County

The Missouri Department of Transportation will install flashing yellow left-turn signals on six intersections along Route K between Hutchings Farm and Mexico Loop in St. Charles County between June 28 and July 5.

The flashing yellow left-turn signals will be installed on Route K at Hutchings Farm Drive, Target, Laura Hill Road, Mill Pond Drive, Clear Creek Drive, and Mexico Loop Road.

These left-turn signals use a flashing yellow arrow, pointed left, instead of a round green signal, to indicate that drivers may make a yielding left turn. Because drivers tend to associate "green" with "go," and "yellow" with "caution," studies have shown that drivers more easily understand the flashing yellow arrow. These new signals also use red arrows instead of the traditional round red signals. Current signs at the intersection will be replaced with a new sign "Left Turn Yield on Flashing Arrow."

These signals let engineers adjust the signals based on traffic patterns. Most of the time, drivers will be able to make a yielding left, increasing their opportunities to make left turns safely. During periods of heavier traffic, however, drivers may only have a green arrow, allowing them to make a protected left turn.

MoDOT has used these signals since 2006 on Olive Boulevard in Creve Coeur at the intersections of Mason, Ross/Questover, and Barnes West/Heritage Place. They have also been installed recently in O'Fallon on Route K near I-70, and in Florissant and Hazelwood along Lindbergh Boulevard. These signals are in use at approximately 50 locations statewide.