There are no national park rules that prohibit e-bikes, but regulations vary by national park. Each superintendent has the authority to set their own rules, but it is best to check with each one before making your trip. Some parks allow them, while others do not. If you are unsure, check with the local visitor center. A ranger can answer your questions about the regulations and other details.
The NPS failed to comply with the law under NEPA, preventing individual park units from considering the effects of e-bikes. The agency did not consider the full negative impacts of e-bikes on ecosystems or other sensitive areas. Instead, it ignored public input and did not give local communities the opportunity to weigh in on the issue. It also did not consider alternative modes of transportation.
The National Park Service recently changed its policy, allowing e-bikes in certain areas. However, there are specific rules for each type of e-bike, and a few national parks prohibit the use of e-bikes on all trails. Canyonlands and Arches are two examples of this. These parks follow federal rules on vehicle use. Since e-bikes are classified as motorized vehicles, they cannot be used on hiking trails. In addition, off-road vehicle use is prohibited on all park property, including backcountry areas.