Nothing in sections 40-4-106 (2), C.R.S., 43-4-201, 43-4-204, 43-4-205, 43-4-206 (1), 43-4-207 (1), and 43-4-208 (1) shall be construed to affect, change, or modify in any way the existing law of this state concerning the responsibility or liability, if any, of the state or any agency thereof, or of any city, town, city and county, county, or other political subdivision of the state, or of any person, firm, or corporation, for any collision, accident, or occurrence at, about, or connected with any crossing of any public highway or road over the tracks of any railroad or street railway corporation.