Depending on the nature of the project, Tribes must use the latest edition of the following design standards, as applicable. Additional standards may also apply. In addition, Tribes may develop design standards that meet or exceed the standards listed in this appendix. To the extent that any provisions of these standards are inconsistent with ISDEAA, these provisions do not apply.

1. AASHTO Policy on Geometric Design of Highways and Streets.

2. AASHTO A Guide for Transportation Landscape and Environmental Design.

3. AASHTO Roadside Design Guide.

4. AASHTO Guide for Selecting, Locating and Designing Traffic Barriers.

5. AASHTO Standard Specifications for Highway Bridges.

6. AASHTO Guidelines of Geometric Design of Very Low-Volume Local Roads (ADT less than or equal to 400).

7. FHWA Federal Lands Highway, Project Development and Design Manual.

8. FHWA Flexibility in Highway Design.

9. FHWA Roadside Improvements for Local Road and Streets.

10. FHWA Improving Guardrail Installations and Local Roads and Streets.

11. 23 CFR part 625, Design Standards for Highways.

12. 23 CFR part 630, Preconstruction Procedures.

13. 23 CFR part 633, Required Contract Provisions.

14. 23 CFR part 635, Construction and Maintenance.

15. 23 CFR part 645, Utilities.

16. 23 CFR part 646, Railroads.

17. 23 U.S.C. 106, PS&E.

18. 23 U.S.C. 109, Standards.

19. DOT Metric Conversion Plan, October 31, 1991.

20. MUTCD Manual of Uniform Traffic Safety Devices.

21. Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects.

22. FHWA-approved State standards.

23. FHWA-approved Tribal design standards.