The council shall have authority to construct and maintain bridges and culverts where needed; and to grade, pave, curb, gravel, plank, and otherwise improve and repair the highways, streets, lanes, avenues and alleys of the village.

     The expense of constructing and maintaining bridges, and the whole, or such part as the council shall determine, of the expense of improving and working upon the streets and highways, including grading, paving, and graveling, may be paid from the general highway fund, to be raised by tax upon all the property in the village. All or part of the expense of grading, paving, or graveling any street may also be defrayed by a special assessment upon the lots and premises abutting upon the improvement, in proportion to their number of feet front upon the street. The lots and premises to be assessed according to their frontage upon a street improvement constitute a special assessment district. As used in this section, "paving" includes curbing and the construction of crosswalks in the paved streets.

     Assessments made under section 18 upon exempt public lands may be paid from the general highway fund, or may be apportioned to the other assessable lots, at the option of the council. If because of the shape or size of any lot an assessment thereon in proportion to its frontage would be unjust and disproportionate to the assessment upon other lots, the council making the assessment may assess the lot for such number of feet frontage as in their opinion is just.