Selection of Crash Cushions

Selection of the most appropriate crash cushion depends on site characteristics, perfor­mance of the systems, maintenance characteristics, and life-cycle cost. Both the geometrical conditions encountered and the space requirements for the different systems vary widely. Obstacles greater than 16 ft (5 m) wide can be shielded by systems such as arrays of sand-filled barrels, or the bullnose attenuator. Where space is limited, narrow systems are appropriate. The structural and safety characteristics of alternative systems must be carefully reviewed and matched with needs. Items to consider include impact deceleration, redirection capability, impact debris, and anchorage and backup require­ments. Table 6.10 has been prepared to compare the maintenance requirements of the different systems. Agency maintenance records should be used to establish associated costs. After potential systems have been identified for a given site, the final selection should be based on a life-cycle cost analysis. (See Chap. 10.) Costs to consider are the initial cost of the device, site preparation and installation costs, and maintenance costs, as well as the cost of accidents.