text: usps regulations regarding rural mail boxes:placing on roadsides, height from road surface,? i am in charge of installing a bank of personal size mail boxes and have been told they must be put on the roadside, not alongside the lane leading into the private community. i would appreciate any information regarding the regulations on placement of mail boxes, in particular, distance from ditch or how far up on side of roadway i can put them. i plan on installing them on double rails fastened to posts in the ground and going parallel with the roadway. there will be room for about 21 boxes on the rails. any information on this would be greatly appreciated. thank you! 1-800-ask-usps.