25 CFR § 170.409
What is the purpose of long-range transportation planning?
February 24, 2021
(a) The purpose of long-range transportation planning is to clearly demonstrate a Tribe's transportation needs and to develop strategies to meet these needs. These strategies should address future land use, economic development, traffic demand, public safety, and health and social needs. The planning process should result in a LRTP.
(b) The time horizon for a LRTP should be 20 years to match State transportation planning horizons.