Various local municipalities have rules about how snow must be removed from properties and walkways after a storm.

Ann Arbor

From Field Operations and Ann Arbor Police:

All snow and ice which has accumulated on the adjacent public sidewalk prior to 6am must be removed by noon. Immediately after the accumulation of ice on such a sidewalk it must be treated with sand, salt or other substance to prevent it from being slippery.

Within 24 hours after the end of each accumulation of snow greater than 1 inch, the owner of every residentially zoned property must remove the accumulation from the adjacent public sidewalk and ramps leading to a crosswalk. Ice must be treated as mentioned above and removed within 24 hours after formation.

Ypsilanti

Ypsilanti gives priorities for street snow removal to state trunk lines and major streets, which are to be cleared bare of ice and snow "as soon as reasonably possible after the winter storm event, without working overtime."