Neb. Rev. Stat. § 60-3,182

(1) All agreements, arrangements, declarations, and amendments authorized by sections 60-3,179 to 60-3,182 and 60-3,198 shall be in writing and shall become effective when filed in the office of the director. (2) Agreements or arrangements entered into or declarations issued under the authority of sections 60-3,179 to 60-3,182 may contain provisions denying exemptions, benefits, and privileges granted in such agreements, arrangements, or declarations to any truck, truck-tractor, trailer, or bus which is in violation of conditions stated in such agreements, arrangements, or declarations.