This paper describes the validation of a surrogate vehicle for luminaire-support testing. The history of surrogate vehicle development is briefly recounted, and a proposed validation process is discussed in detail. Four levels of validation are described. Level 1 relates force-deflection characteristics between the surrogate and an actual automobile, while level 2 considers velocity-change comparisons. Level 3 focuses on crush-length comparisons, where the concept of normalised crush is introduced. Finally, level 4, the highest level of validation, is based on physical-modeling comparisons. For the purposes of evaluation of luminaire supports and sign posts, it is suggested that validation of a surrogate at levels 1 and 2 only is sufficient to meet the requirements of the american association of state highway and transportation officials (AASHTO) specifications. Test results are then presented for the new surrogate vehicle, being used by the federal highway administration (FHWA), when impacting luminaire supports mounted on different types of bases. The FHWA surrogate is shown to be validated for evaluation of the breakaway performance of luminaire supports mounted on either transformer bases or couplings. Not only is validation achieved for levels 1 and 2, but also partially for level 3 and level 4. It is recommended that the proposed validation technique be reviewed by the highway research community and considered for future validation of surrogate vehicles. Further, it is recommended that the breakaway bogie, developed under research sponsored by the FHWA, be accepted by the roadside safety community for use in evaluating breakaway luminaire supports.
Samenvatting