29 CFR §1917.124

1. (a)General. The employer shall provide safe means of passage between different surface levels and across openings.
2. (b)[Reserved]
3. (c)Dockboards (car and bridge plates).
   1. (1)Dockboards shall be strong enough to support the loads imposed on them.
   2. (2)Portable dockboards shall be anchored in position or be equipped with devices to prevent their movement.
   3. (3)Hand holds or other effective means shall be provided on portable dockboards to permit safe handling.
   4. (4)Positive means shall be used to prevent railcars or highway vehicles from being moved while dockboards or bridge plates are in position.
   5. (5)Be designed, constructed, and maintained to prevent vehicles from running off the edge. 10
   6. (6)Dockboards shall be well maintained.
4. (d)Ramps.
   1. (1)Ramps shall be strong enough to support the loads imposed on them and be designed, constructed, and maintained to prevent vehicles from running off the edge. 11
   2. (2)Ramps shall be equipped with a guardrail meeting the requirement of § 1917.112(c)(1) if the slope is more than 20 degrees to the horizontal or if employees could fall more than 4 feet (1.22 m).
   3. (3)Ramps shall have slip-resistant surfaces.
   4. (4)When necessary to prevent displacement by vehicle wheels, steel plates or similar devices used to temporarily bridge or cover uneven surfaces or tracks, shall be anchored.
   5. (5)Ramps shall be well maintained.