https://www.sciencedaily.com/releases/2020/10/201021130136.htm

In the study, which appeared online September 30 in the journal Landscape and Urban Planning, the researchers examined publicly available Google data based on anonymized mobility information from millions of Android, iPhone, and Google Maps users in the United States to destinations including grocery stores, rail stations, and parks. The researchers analyzed how total movements changed, at the county level, following local shelter-in-place orders. They found relatively large reductions in visits to "essential" destinations such as grocery stores -- but effectively no reduction in "non-essential" visits to parks and other outdoor recreational spots such as parks and beaches.

The analysis, which included all 771 metropolitan counties in Google's dataset from the first day of stay-at-home order in each county until May 11, 2020, showed that in counties classified as densely populated, reductions to essential trips were even more pronounced.