This guide is intended to provide assistance in the warranting, selection, and design of roadside barriers. The guide is prepared specifically for warranting, selecting, and designing barriers on Federal Lands Highways projects that are low volume and/or low speed facilities. The guidelines present practical and useful guidance for common conditions and situations encountered in the design of roadside barriers for Federal Lands Highway projects. Warranting of roadside barriers is a process that involves determining the needed clear zone, identifying potential hazards, analyzing strategies for corrective action, and evaluating the use of roadside barriers. This process is designed to identify only the most severe hazards close to the roadway that are appropriate for shielding by barriers. It takes into account both the cost of a barrier and the expected crashes into that barrier. Local conditions, policies, and resources are also considered in this process. The barrier selection process includes consideration for speed, hazard offset and special design considerations for aesthetics and severe conditions. These considerations lead to a list of technically acceptable barriers for a specific site. Additional selection criteria are suggested for final barrier selection. Roadside design and placement criteria expand on the AASHTO Roadside Design Guide design process, making it more applicable to low volume, low speed rural conditions. An alternate design process is included for locations with restricted conditions or severe cost constraints. (Author/publisher)
Samenvatting