The east and west portals, respectively, of the 318-foot-long Olowalu Tunnel at mile 10.4 on the Honoapiilani Highway (state route 30), along Maui’s southwest coast west of Maalaea Harbor.  Built in 1951, this is the oldest highway tunnel in Hawaii. On the mauka (inland) side of each portal is wire netting to keep rocks from falling onto the roadway.