The presence—or rather, the absence—of a turn lane, especially when considering the intense peaking associated with a
school, can affect traffic operations around the school. The congestion, in turn, can influence the operations and safety of
the pedestrian and bicyclist school trips. Some agencies have guidelines for the installation and design of turn lanes for
access to adjacent sites, while others cite the AASHTO Policy on Geometric Design of Streets and Highways—also known as
the Green Book—as a primary source for their turning lane criteria.4
Installation of turn lanes is particularly important to
consider when school sites are located on high-speed roadways, where separation of turning movements from through
traffic provides operational and safety benefits.