Type M30 steel beam guide rail (SBGR) is a TL-3 MASH Longitudinal barrier guide rail system. Type M30 SBGR is a version of the Midwest Guardrail System (MGS) with 12 in (30 cm) plastic blocks. Type M30 SBGR has an extended block to be able to achieve the same alignment of face of rail while curb and sidewalk are present.