Section 810.108 - Designation of existing facilities(a) In accordance with the provisions of 23 CFR 810.102 , the Federal Highway Administrator may approve on any Federal-aid system the work necessary to designate existing parking facilities (such as at shopping centers or other public or private locations) for fringe and transportation corridor parking. (1) Eligible activities include the acquisition of or the initial and renewal costs for leasing existing parking space, signing of and modifications to existing facilities, trail blazer signs, and passenger loading areas and facilities.(2) The approval criteria in 23 CFR 810.106(a)(1), (4), (5), (7) and (8) apply to these parking facilities.(b) In accordance with the provisions of 23 CFR 810.102 , the Federal Highway Administrator may approve on any Federal-aid system the work necessary to designate existing highway lanes as high occupancy vehicle lanes. (1) Eligible activities include preliminary engineering, signing, pavement marking, traffic control devices, minor physical modifications and initial inspection or monitoring of use.(2) Such improvements may be approved on any public road if they facilitate more efficient use of any Federal-aid highway.(c) Interstate construction funds may be used only where the proposed projects were approved in the 1981 Interstate Cost Estimate.