The board, in assessing the benefits derived by any land in such district, shall consider only its proximity to the road and its market terminus. No benefit assessment shall be made on any lands when the distance between it and the nearest point on the road is greater than three tenths of the distance from such point on the road to the market terminus of the road, and no benefit assessment shall be made on any land more than three and one-half miles from the road. Any subdivision of a section of land containing forty acres, more or less, for the purposes of the benefit assessment may be included in such district if one fourth thereof is within the lines of the district. The board may collect from a benefit district an amount equal to One Thousand Dollars ($1,000.00) for each lineal mile of road constructed therein, and no more, except interest on the amount that may be expended twelve months or more in advance of the collection of any tax. The board shall not undertake the construction of any road when the estimate indicates that the total cost will exceed Thirty-five Hundred Dollars ($3,500.00) per mile.