sphalt road curved on the mountain at khao kho

road highway lane infrastructure freeway asphalt tarmac transport racetrack overpass traffic vehicle street track reservoir asphalt curve cliff country caution careful carefully countryside danger drive direction distance downhill destination electric forest freeway high hill highway khao kho line long lane mountain nature notice pass path pole phetchabun ride route road rock rural roadside roadway slope shape speed street sightseeing sidewalk sky stone sign tree traffic transportation tarmac thailand uphill view voltage vehicles warning white yellow