Crown raising guideline

Crown raising removes the lower branches of a tree in order to provide clearance for vehicles, pedestrians, and buildings. The City of Portland requires maintaining clearance standards 7½ feet above the sidewalk, 11 feet above residential streets, and 14 feet above main arterial streets.

From the city of Naperville's website -

The City trims to a level of 12 feet over the curb line to provide enough clearance for truck traffic. In more developed areas which contain mature trees, the City concentrates on removing dead tree limbs.

From the village of Downers Grove's website-

With a legal vehicle height limit of 13.5 feet (see Illinois Motor Vehicle Code 625 ILCS 5/15-103) the Forestry Division has chosen 14 feet as the target clearance for over the street.  

From the city of Berwyn 2020-2022 tree maintenance contract -

The pruning shall consist of removing all dead limbs, crossing limbs and limbs lower than 18 feet on a mature tree.  

Note: This Berwyn guideline has resulted in the butchering of a large number of trees over several years.