Nothing herein shall prevent any county from employing, by agreement with not more than four (4) other counties, the same engineer to act as county engineer for each and all of said counties so agreeing. Each county engineer shall give bond, with sufficient surety, to be payable, conditioned and approved as provided by law, in a penalty not less than Fifty Thousand Dollars ($50,000.00). If a county engineer is engineer for two (2) or more counties, the same bond shall serve as said engineer's bond in and for each county, respectively, and the premium on said bond and the salary and expenses of such engineer and assistants shall be divided between and paid by the counties for whom he is so employed in such proportions as may be agreed upon by said counties. In the event any county is unable to obtain the services of a competent engineer, the Transportation Commission may loan such county an engineer, if available, for a specified period of time, by granting such engineer a leave of absence for such period without loss of any benefits accruing to him by reason of length of service; and such time so spent on such leave of absence shall be counted as part of such engineer's length of service with the Department of Transportation. The salary of such engineer so loaned shall be paid by the county or the counties to whom he is loaned.
The salary and other expenses, including the premium on all bonds, of the county engineer and his assistants shall be paid by the county or counties employing such county engineer and assistants. Any salary limitations or ceiling heretofore placed by law on the salary of a county engineer is hereby removed as to county engineers employed under the terms of this chapter. In lieu of salary and other expenses, any county may employ a registered civil engineer on a fee basis for furnishing complete engineering services on state aid projects. Engineering costs, including the salaries or fees of the county engineer, incurred on state aid projects may be paid from state aid funds allocated to said county or counties, with the methods of payments to be approved by the State Aid Engineer under regulations promulgated by the State Aid Engineer; however, unless the project is being partially funded with federal funds, no such costs shall be paid to the county from state aid funds prior to the approval for advertisement for bids for a project by the State Aid Engineer. If the project is being partially funded with federal funds, the State Aid Engineer may approve payment of a portion of such costs from state aid funds prior to the approval for advertisement for bids.