Charges for longer and shorter hauls; governing rate.

It shall be unlawful for any common carrier subject to the provisions of this act to charge or receive any greater fare or rate for the transportation of passengers or like kinds of property under substantially similar circumstances and conditions for a shorter than a longer distance over the same line, in the same direction, the shorter being included within the longer distance, but this act shall not be construed as authorizing any common carrier within the terms of this act to charge and receive as great compensation for a shorter distance as for a longer distance: Provided, however, That upon application to the commission appointed under the provisions of this act such common carrier may, in special cases after investigation by the commission, be authorized to charge less for longer than for shorter distances for the transportation of passengers or property, and the commission may from time to time prescribe the extent to which a designated common carrier may be relieved from the operation of this section of this act. When there are 2 or more rates in effect between the same points, via the same route, the lowest published rate shall be the only legal rate applicable in this state. In the event a published through rate exceed any combination of 2 or more local rates between the same points within the state, the combination forming the lowest rate shall govern.