Mo. Rev. Stat. § 142.350
The funds herein provided for the construction of state highways shall be distributed between the higher type roads (herein referred to as the primary system) and the other state roads (herein referred to as the secondary system) on the basis now prevailing, that is, forty-eight and eight-tenths percent to the primary system and fifty-one and two-tenths percent to the secondary system, and such basis of distribution shall be continued until one of these systems shall have been completed, and thereafter all of the funds provided for construction purposes shall be used in the construction of the roads of the remaining system; provided, however, that such sums as the commission shall determine are necessary each year to reimburse counties and other civil subdivisions for state highways constructed wholly or in part at their expense and accepted by the commission, and such sums as in the judgment of the commission shall be necessary for maintenance of state highways shall first be deducted from the funds herein provided for before distribution between the primary and secondary system for construction purposes is made; provided further, that sufficient funds to provide for the payment of principal and interest on outstanding state highway bonds as now required by law shall be available from revenue under the provisions of existing laws or pursuant to this chapter before any distribution of funds is made as herein provided.
§ 142.350, RSMo
Effective 1/1/1999