Neb. Rev. Stat. § 39-1342

The department shall have the authority to construct and maintain highway illumination and sidewalks along such parts of the state highway system as are necessary for safety and public welfare. The department may also erect and maintain any other appurtenances to the state highway system which the department deems necessary for safety and public welfare. Appurtenances shall include, but are not limited to, sidewalks, storm sewers, guardrails, handrails, steps, curb or grate inlets, driveways, fire plugs, and retaining walls.