Overview

• The Federal Highway Administration’s first traffic sign manual update since 2009 specifies that the 85th percentile method should not be the sole factor in setting speed limits.
• The new guidance directs engineers to consider pedestrian exposure, land use and crash history in addition to observed vehicle speeds when posting limits.
• Ohio has revised its rules to let municipalities apply the 50th percentile speed for roads with heavy foot or bicycle traffic and is reviewing further changes.
• A Lucas County study found Sylvania Township’s Mitchaw Road speed limit of 55 mph falls 5 mph below the 85th percentile measurement but cannot be adjusted under current state law.
• Research from the Insurance Institute for Highway Safety shows every 5 mph increase in state maximum speeds raises interstate fatalities by 8.5%, and urban pilots in Madison and Seattle report fewer serious injuries after reducing limits.