A. No public highway or street shall be constructed across the track of any railroad at grade, nor shall the track of any railroad corporation be constructed across the track of any other railroad at grade, without the permission of the commission, but this provision shall not apply to the replacement of lawfully existing tracks. The commission may refuse permission or grant it upon such terms and conditions as it prescribes.

B. The commission shall have the exclusive power:

1. To determine and prescribe the manner, including the particular point of crossing, and the terms of installation, operation, maintenance, use and protection of each of the crossings.

2. To alter or abolish crossings.

3. To prescribe the terms upon which and the proportions in which the expense of the alteration or abolition of the crossing shall be divided between the parties affected or in interest.

C. When the commission finds that public convenience and necessity demands establishment, creation or construction of a crossing of a street or highway over, under or upon the tracks or lines of any public service corporation, the commission may by order require the establishment, construction or creation of the crossing, and the crossing shall thereupon become a public crossing. The commission shall have the exclusive power to prescribe the character of crossings to be constructed and maintained by railroads where their lines cross public roads or streets of a town or city.