The Wyoming Department of Transportation utilizes two standard traffic signal pole designs. These designs are based on four load cases which depict the maximum loading and the associated pole and signal arm properties.
Signal arms vary in length from 10 to 55 feet and may be either curved or straight.
The design conforms to the 2009 AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires and Traffic Signals, 5th Edition.
Design wind pressures are based on a 90 mph fastest-mile wind speed with a 1.3 gust coefficient in accordance with Appendix C. Fatigue Importance Category II is used for fatigue design. Fatigue design loads are the natural wind gust pressure range based on a yearly mean wind velocity of 12.9 mph, and truck-induced gust pressure range based on a truck speed of 55 mph.