Mo. Rev. Stat. § 227.040: Engineer to make surveys, plans, specifications.

The engineer shall proceed to cause surveys to be made of the state highway system as designated in section 227.020, and to prepare detail plans and specifications for each part thereof as soon as practicable; provided, however, that wherever surveys have heretofore been made, it shall be the duty of the engineer, when practicable, to adopt and utilize such surveys, together with plans and specifications if any have been made by the transportation department.