All E-Bikes are restricted to use on trails and roads opened to motorized vehicles only on Federal lands.
No free pass to non-motorized trails and roads.
Where can I ride now?
The National Park Service (NPS) final rule issued in December 2020 generally states that e-bikes may go where traditional bicycles are allowed. However, superintendents at each park must give explicit direction to “limit or restrict” access for e-bikes, where they deem appropriate. There’s no blanket allowance, says Morgan Lommele, director of state and local policy for People for Bikes, an industry group that advocates for e-bikes.
So, e-bike rules for different parks may appear over time on a park-by-park basis. Before you visit, check a park’s website to find out which trails are accessible to e-bikes. (Use this park locater to plan your visit).
Redwood National Park in California, for example, allows e-bikes on most “hike/bike” trails, except four that cross into state park boundaries. In Utah’s Zion National Park, only Class 1 e-bikes are allowed where traditional bicycles are. Meanwhile, you can ride your e-bike (or bike) only in certain areas of Grand Canyon National Park. And in Yosemite National Park, e-bikes are also allowed where bicycles are allowed. However, mountain biking—and thus electric mountain biking (eMTB) on dirt trails—is not permitted in Yosemite.
https://www.rei.com/blog/cycle/ride-e-bike-federal-lands