This route is currently signed as country road J1 from Highway 25 South of Hollister to 180 in Mendota, in Fresno County.
It is proposed Route 180 in the Streets and Highways code.
On old maps from the 1960s until 1984 you will see 180 signed along this route, and further along 25 until US101 just south of Gilroy.
If 180 was finished it could take one of two routes. The current route of J1 is longer than Little Panoche Road, which takes a more direct course. Little Panoche Road is a dirt road from the tiny town of Panoche to Interstate 5. I actually tried to do it once, and that was a mistake. Not only is it dirt, it has streams several feet deep crossing the road bed.
J1 leaves 25 as a wide, fast route. The quality of the road and bridges decline as you head east in San Benito County. It gets narrower and slower (25 mph or so) as you enter the hills near Panoche Pass (2800' up or so.) Then it becomes one lane wide for a while going down the Pass. It has many bad curves and poorly banked sections that can throw your car airborne if you're not careful. It straightens out in the Panoche Valley and climbs the hills near the Fresno County line. Near the Fresno County line it goes over Shotgun Pass (1650' up). From there to Interstate 5 it is mainly 40-45 MPH and two lanes wide. It passes near a reservoir a few miles west of Interstate 5. If you continue on to Mendota, you will rejoin the existing route 180, go through Fresno on some new sections of freeway, and then go into Kings Canyon National Park.
This is J1 right at 25. This is from May 1995. The other photos are from 3/1997 and 3/20/2008, which was
the best I have ever seen this road, and luckily I had my digital
camera with me. I went back on 3/26/2008 for more photos and they're
some of the best I have taken!
You see this mile sign just at 25, in Paicines: