A 25 mile-per-hour speed limit applies on streets in most residential and retail areas unless otherwise posted. On arterial and other busy streets, higher speed limits are often allowed.
New speed limits must be established in accordance with state and federal guidelines. Speed limits are set by the prevailing speed. This is measured by calculating a speed that less than 15 percent of motorists exceed. The prevailing speed is slightly less than the 85th percentile speed. Unless there are unusual circumstances, streets have speed limits that are within a five mile-per-hour increment of the prevailing speed.