All-too-familiar orange traffic cones direct drivers and divide lanes in road construction zones and during maintenance projects. They are easily recognized across the country because the U.S. Department of Transportation's Federal Highway Administration sets minimum traffic cone standards for maximum safety and effectiveness.
General National Traffic Cone Standards
All traffic cones must be orange, florescent red-orange or florescent yellow-orange. Daytime and low-speed area cones on roads at or below 40 miles per hour must be at least 18 inches tall; cones intended for freeways and high-speed areas -- above 45 miles per hour -- must be at least 28 inches tall. All cones must be stable enough to withstand environmental and traffic conditions, so they can be doubled up or weighted down. Flashing lighting devices can be attached to cones if the lights increase visibility in bad weather, on curvy roads or in areas with many distractions.
Night-use cones must be at least 28 inches tall and have reflectors or lighting devices. Cones measuring 28 to 36 inches must have two white reflector bands that measure six and four inches wide; if the cones are taller than 36 inches, they must have at least two white reflector bands measuring four to six inches creating alternating orange and white stripes with the top stripe being orange. Non-reflective gaps cannot exceed three inches.
Individual states can have additional requirements, as long as they adhere to the federal standards. These requirements can include more specific sizes or weights, or modifications for specific climates or inclement weather.