Evaluation of warning signs and markings to reduce speeds on curves

Sharp horizontal curves can pose dangers to the driver when dealing with speed adjustment, vehicle placement, and judgment of the appropriate operating speed. Roadway designers use various warning methods to aid drivers in such situations. Two primary methods of achieving this are warning signs and pavement markings. There is a suspicion however that these devices are often misinterpreted or disregarded by drivers. The objective of this study is to evaluate the use of several warning signs and pavement markings at problematic rural horizontal curves, and to evaluate their effectiveness in relation to speed reduction. Several types of warning signs and pavement markings were used to determine methods and combinations that could reduce operating speeds more effectively. The results indicate that the most promising treatments in reducing operating speeds are flashing lights and transverse lines. Another treatment that also showed some potential for reducing speeds is the new combination sign.