Fixed Height Restrictor BarrierFixed Height Restrictor Barrier Our Fixed Height Restrictor Barrier has a standard clearance of 2. 05m and limits access to high sided vehicles such as HGVs and Caravans. Height restrictors are ideal for use on sites where limited overhead clearance will cause problems for high sided vehicles such as multi story or underground car parks. Manufactured from galvanised mild steel, the body of the height restrictor is coated red as standard (other colours