Mt. Diablo’s the tallest mountain in the Bay Area, and the view from the summit is world-class. Most days the whole Bay Area is laid out for you, and on particularly clear days you can see all the way to Yosemite, Mount Lassen or Mount Shasta.
Thousands of people visit the Mount Diablo State Park every week to hike, bike, picnic and sightsee. Therein lies the rub: the park’s Summit Road is famously twisty, narrow (lanes are 8 to 9 feet), and shared between motorists and cyclists. Before 2014, Mt. Diablo saw an average 23 collisions reported per year, about one every two weeks. 2017 saw 10 in total, and only one car-and-bike accident. 2018 is on track to have even fewer accidents thanks to road safety improvements, and, as of this writing, no vehicular collisions at all (keep those fingers crossed!).
The trend is not random chance, statistical noise, or fewer people visiting the park—in fact, 700,000 people visit the park annually.