City and County of Denver v. American Oil Company

Zoning laws are justified only when they are enacted as a proper exercise of the police power. When such justification is absent, they become vulnerable to attack. Parkview Church v. Pueblo, 139 Colo. 98, 336 P. (2d) 310. To be a valid exercise of the police power, zoning laws must subserve to some substantial degree the public health, safety, morals or general welfare. Jones v. Board, 119 Colo. 420, 204 P. (2d) 560. Here is the touchstone of validity — that the zoning regulations have a tendency to promote the public health, safety, morals or general welfare.

An attempt to exercise police…