[Code of Federal Regulations] [Title 36, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 36CFR4.13] [Page 36] TITLE 36--PARKS, FORESTS, AND PUBLIC PROPERTY CHAPTER I--NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR PART 4--VEHICLES AND TRAFFIC SAFETY--Table of Contents Sec. 4.13 Obstructing traffic. The following are prohibited: (a) Stopping or parking a vehicle upon a park road, except as authorized by the superintendent, or in the event of an accident or other condition beyond the control of the operator. (b) Operating a vehicle so slowly as to interfere with the normal flow of traffic.