There is little traffic most of the year, despite the proximity of San Jose, less than 10 miles away but shielded from the coast by impassable mountains. But the closer you get to San Francisco, the more development you find. North of Half Moon Bay, there is only one more brief run of wildness, as the road has to bend around San Pedro Mountain. At the place called Devil's Slide, where the road cuts through a very unstable portion of the mountain, the road often has been closed by landslide. Sometimes the detour is only a short gravel loop, but at other times the only detour has taken drivers 30 miles out of the way through San Mateo.
Conditions are subject to change.
The southern half of the Pacific Coast Highway alternates between the most asphalt-choked cities and the most untamed nature, culminating in the great crescendo of the Big Sur. It can be seen as a kind of symphony, building to a grand outburst of brass and timpani, then quieting down to a final city cadence. You can reacquaint yourself with the elemental forces of rock, water and air and recharge your batteries. But there are some people who say it gets even better. North of San Francisco, there is almost nothing but nature.