Design of roadside barrier systems for MSE retaining walls

There is confusion among civil engineers in the United States regarding the applicable design method and the appropriate impact load for sizing the moment slab of roadside barrier systems atop MSE retaining walls. The design method and impact load discussed herein have been used successfully for more than 15 years to size the barrier moment slab and to determine the magnitude of loads applied to the supporting MSE wall. The source of confusion by civil engineers is explained and the current research to eliminate this confusion is described.