Much as the name implies, AASHTO’s “Complying with Section 4(f) of the U.S. DOT Act” assists practitioners in managing Section 4(f) compliance. Section 4(f) is a law that protects public parks, recreation areas, wildlife and waterfowl refuges and significant historic sites.
All in all, it’s a fairly comprehensive resource about Section 4(f) questions, practices and documentation. I especially like Appendix B—Special Rules and Exceptions for Section 4(f) Applicability Findings. Appendix B points you towards specifically applicable regulations based on property types (i.e. golf courses, fairgrounds and zoos).