16 U.S.C. § 8542 — Permit flexibility

(a) In general. The Secretary in charge must set guidelines letting a special recreation permit holder do a different recreational activity under the same permit, as long as it is substantially similar to the activity the permit already covers. (b) Criteria. An activity counts as "substantially similar" only if it meets four tests. It must be like the original activity in type, nature, scope, and setting. It must not harm resources more than the original activity would. It must not hurt other permit holders or other approved uses of the land. And it must follow all applicable laws and the area's land or resource management plan. (c) Surrender of unused visitor-use days. A provider holding a certain type of long-term permit (described in section 6801(13)(A)(iv)) may tell the Secretary it cannot use all its allotted visitor-use days for the year, and give those unused days back for temporary reassignment to someone else under section 8547(b). Before the provider gives up a day, it can ask the Secretary to check and confirm whether that unused day meets the requirement in section 8546(b)(3)(B), so the provider can decide with good information. (d) Effect. Nothing in this section changes any other federal law, rule, or decision about using electric bicycles on federal recreational lands and waters.