Okla. Stat. tit. 74 § 291.1b
Members of the Legislature shall receive mileage reimbursement pursuant to Section 500.4 of Title 74 of the Oklahoma Statutes for the number of miles necessarily and conveniently traveled by the most usual and feasible route to be present upon convening of the regular or extraordinary sessions of the Legislature by such member in each and every trip in going to and returning from the place of meeting of the Legislature. Each member shall be entitled to mileage reimbursement for one (1) round trip per week in traveling to and from the meeting of the Legislature. A member not claiming per diem reimbursement may elect to receive mileage for not to exceed as many trips as there are legislative days for a week during each week the Legislature is actually in regular or extraordinary session, provided that no single, round-trip mileage reimbursement may exceed the per diem allowance. Members of the Legislature shall receive mileage reimbursement, for the use of privately owned vehicles pursuant to Section 500.4 of Title 74 of the Oklahoma Statutes for the number of miles necessarily and conveniently traveled by the most usual and feasible route to be present in attending meetings of committees of which they are members or to which they are invited by Committee Chairmen when the Legislature is not in session, subject to the approval of the presiding officer of each house for the members of the respective houses.
Okla. Stat. tit. 74, § 291.1b