Ind. Code § 8-23-6-5
This chapter does not annul, limit, or abridge the right of a city or town, either at its own expense or at the expense of property owners subject to assessment, to improve the sidewalks and curbs along a street forming the route of a state highway, to construct sewers and drains, or to construct or maintain a part of the roadway of the street not improved or maintained by the department. The city or town shall provide adequate drainage for the street except as otherwise provided in this chapter. Except as expressly provided in this chapter and subject to IC 9-21, this chapter does not limit the right of a city or town to regulate traffic over a street over which a highway is routed or to relieve the city or town of liability now imposed by law. The cost of improvement, except as otherwise provided in this chapter, shall be paid for out of the funds appropriated to the department. Whenever a person, firm, limited liability company, or corporation, other than a municipal corporation, is required or obligated by a law, ordinance, or contract to keep in repair or to maintain or to construct a street, any part of a street, or any railroad, interurban railroad, or street railroad crossing, or any structure or bridge thereon, this chapter does not relieve the person, firm, limited liability company, or corporation or the receiver thereof from the duty, obligation, or contract.
IC 8-23-6-5