excerpt from article about regulating and calculating time in ways different to broadcast news media and everyday consumer worlds,
...within Arizona, which recognizes Mountain Standard Time year-round, the case gets more confusing for anyone traveling through the Hopi and Navajo nations. Both nations are in the same area–in fact, the Navajo nation completely surrounds Hopi territory, and both nations have enclaves within the other.
This arrangement might not have much of an impact time-wise, except that the Navajo nation uses daylight savings time, while the Hopi nation, along with the rest of Arizona, does not. Essentially, it'd be possible to drive through each outlying city and change time zones five times, all within two hours.