The annual Hood to Coast Relay race will take place Friday and Saturday, and that means 17,000 runners and walkers expected to travel along several Oregon highways.  The route will take race participants from Timberline Lodge on Mount Hood to Seaside.  Travelers need to watch for runners and walkers, as well as approximately 3,000 support vehicles involved in the event, which begins Friday morning.  The second leg of the relay will take runners through a construction site on Highway 26 west of Government Camp where ODOT is cutting back the steep slopes along the highway to reduce rockfall.  Along nearly a two-mile stretch runners will run outside of a concrete barrier with a slightly narrower shoulder.  The contractor will not work on the day runners are heading down the mountain.  Drivers on Highway 26 are asked to use extra caution and be alert in this area.  State and city police agencies along the relay route will have a visible patrol enforcement presence.