 State Route 174 ( SR 174 ) is a state highway in the U.S. state of California . The two @-@ lane 13 @-@ mile ( 21 km ) highway , added to the state highway system in 1933 , connects Interstate 80 in Colfax with SR 20 / SR 49 in Grass Valley , crossing the Bear River next to a 1924 concrete arch bridge . The majority of the highway is eligible for the State Scenic Highway System , but local residents have blocked its designation due to property rights concerns . 
