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Turn Control Signs

What are they?

no left turnright turn onlydo not enterTurn control signs are regulatory devices used at intersections to prohibit or designate specific turning movements.

Why do we have them?

Turn control signs are used for predominantly two main reasons. They are used as a safety device and to facilitate more efficient traffic flow by restricting certain turning movements which may unnecessarily delay traffic. Turn control sign messages have evolved over the years to the point that the restrictions may be in effect on a full time basis, for only a portion of the day, or only whenever certain conditions exist.

Where do we have them?

As safety devices, full time turn control signs are especially important at intersections to prevent motorists from turning the wrong way into a one-way street; and, they may be used to restrict turns which are hazardous due to prevailing speeds or roadway alignment. Full and part time turn controls are also very effective in increasing the vehicular capacity of intersections by eliminating turns which can cause unnecessary delays to other major traffic movements. Turn controls which are only in effect for certain conditions may restrict movements such as "right turns on red" where these turns would be in conflict with other major vehicle movements which may not be obvious due to the size and design of the intersection.

What are the issues?

  • Turn control signs are a valuable traffic control device when used under the right circumstances. They promote safety and efficiency throughout a roadway network. Drivers learn to expect, understand and respect appropriately installed signs.
    Signs cannot always by themselves restrict motorists who choose to wilfully make illegal turns. Therefore the signs must often be supplemented with physical obstructions such as concrete medians or other forms of barriers when and where conditions warrant. This is often true at major driveway locations.
  • Turn control signs are often ineffective when installed for reasons other than safety or to improve traffic flow. Those used to mitigate through traffic from using local streets are seldom respected by most motorists and often must be supplemented by physical barriers to be truly effective. Without physical barriers, these signs may require significant police presence and can generate public relations problems.