JavaScript must be enabled in order to use this site.Please enable JavaScript in your browser and refresh the page. BD21/01 Specific Parameters Used to input parameters for loading per BD21/01 "The Assessment of Highway Bridges and Structures". SettingDescription Loading Class Select the Assessment Loading vehicle from this list per Cl.5.12 through 5.17 of BD21/01 Road Class Select the bridge situation in terms of road surface characteristics and traffic level per Cl.5.22 of BD21/01. Parent topic: Load Generator Parameters dialog