State Highway 9 (SR9) between Santa Cruz and Felton has been closed for major construction, which makes it super nice to ride bikes on. Be warned that CHP have been known to ticket cyclists who venture beyond the road closure, and there's no way to get through the actual construction area itself (it's covered with heavy equipment).
People Power Santa Cruz (the human powered transportation advocacy group in Santa Cruz) have been campaigning for years to close this stretch of Highway 9 along Henry Cowell State Park. There are no homes or businesses along this section, but this highway is the main access to Santa Cruz for residents of Felton and the upper San Lorenzo Valley and it's an important evacuation route in case of wildfire or flooding, both of which can strike quickly in this valley.
Interestingly, this closure has apparently resulted in increased business for shops in Felton, with the exception of a gas station at the south end of Felton.