are tall enough to impact not only a vehicle's tires but the vehicle body itself. They usually contain one or more retroreflective strips. They can be round and open in the center or curved (45-degree sections) of plastic with a reflective strip. They are also used in low reflective markers in a "T" shape. They can also be used to indicate lane closures as in cases where the number of lanes is reduced. The name "delineator" is also used for reflective devices attached to other objects which are technically not pavement markers. See also Road surface marking Rumble strips References External links Road infrastructure Road surface markings British inventions 1933 introductions American inventions