It is desirable from the standpoint of sight distance, rideability, braking, and acceleration distances that the intersection of roadway and railroad be made as level as practical. Vertical curves should be of sufficient length to provide an adequate view of the crossing.

In some instances, the roadway vertical alignment may not meet acceptable geometrics for a given design speed because of restrictive topography or limitations of ROW. To prevent drivers of low-clearance vehicles from becoming caught on the tracks,

the road crossing surface should be level with the top of the rail for a distance of 2-ft from the nearest rail and not more than 3 inches higher or lower than the top of the nearest rail at a point 30-ft from the rail,

as shown in . Vertical curves should be used to traverse from the roadway grade to a level plane at the elevation of the rails. Rails that are superelevated, or a roadway approach section that is not level, need a site-specific analysis for rail clearances.