Abstract:
A transition is defined as a section of barrier used to produce the gradual stiffening of a flexible or semi-rigid barrier as it connects to a more rigid barrier or fixed object. These transitions should provide an effective transition between longitudinal barriers with different lateral stiffness and redirect impacting vehicles without any contact with the rigid barrier. Stiffer transitions can be accomplished through the use of additional posts with reduced post spacing, larger posts, doubled (nested) rail elements, rubrails, and other special features such as use of a stiffer semi-rigid barrier such as a thrie-beam barrier. Transitions typically are generic designs. NCHRP 350: "Recommended Procedures for the Safety Performance Evaluation of Highway Features," AASHTO’s "Manual for Assessing Safety Hardware," and European Normative (EN) 1317-4 have outlined testing requirements for transitions.
