The Idaho Transportation Board voted unanimously Friday to approve 80 mph speed limits for southern Idaho freeway stretches on Interstates 84, 86 and 15 that now are 75 mph.
In the Treasure Valley, that means I-84 west of Caldwell and east of Boise will increase to 80 mph in early August, as soon as new signs are in place, the Idaho Transportation Department announced after the board meeting in Coeur dAlene.
Speed limits in urban areas from Caldwell to Boise and in Pocatello and Idaho Falls remain at 65 mph, as does I-90 through northern Idaho.
The Legislature passed a law this past session calling for the increase to take effect in rural areas July 1, but concerns from AAA of Idaho and others prompted the board to postpone the change for further consideration.
Idaho Transportation Department staff had recommended the changes after traffic studies showed motorists already are traveling 80 mph on those routes.
Fridays vote came after a long discussion of questions about the changes and with the condition that the new limits be reviewed every year.
Engineering studies on state highways will be completed at later dates before speed-limit changes will be considered, ITD reported.