Coronavirus stay-at-home orders that went into effect on March 20 have reduced vehicle collisions on California roadways by roughly half, according to a UC Davis survey that is the first to estimate the impact of the extraordinary health orders on traffic.

“The reduction works out to about 15,000 fewer collisions per month and 6,000 fewer injury accidents per month,” said Fraser Shilling, co-director of the Road Ecology Center at UC Davis. Shilling said the reduction in motor vehicle accidents on highways and roads, “can be directly or indirectly attributed to the shelter-in-place order.”

The survey suggests that a 60% drop in traffic volume — when compared to the same period last year — accounts for a roughly 50% decline in collisions on roadways policed by California Highway Patrol.