Rationale

At the request of manufacturers, modify Section 16.2 to allow marking of the inside of the "top" surface to be made on the inside face of the sidewall with an arrow indicating the top slab of the culvert as manufactured. The standard covers box culverts with rise dimensions up to 12 ft and greater. With the culvert oriented in the installed orientation, it is difficult to reach the inside face of the top slab without a ladder or some other support for marking. Allowing the top marking as required in Section 16.2 to be applied on the sidewall with an arrow or other means of indicating the inside top surface would allow for compliance with the marking requirements without the need to physically access the inside surface of the top slab.