From time to time, the question about bicycling on freeways (a.k.a. highways, or more officially “controlled access highways”) comes up.
By statute, the state (ADOT) or local authorities may prohibit bicyclists:
§28-733. Restrictions on use of controlled access highway
A. The director may, and local authorities by ordinance may, prohibit the use … by pedestrians, bicycles or other nonmotorized traffic…
ADOT has a formal written policy see:
“bicycles are permitted by law to operate on all State highways, including controlled-access highways, except where excluded by administrative regulation and the posting of signs to give notice of a prohibition”. Which then goes on to list specifically where the prohibitions are, what are generally speaking the urbanized areas. For example the restriction on I-10 is from MP 120.22 (Verrado Way) to MP 270.59 (Kolb Road) — that is the entire Metro Phoenix through Metro Tucson region.
Besides ADOT (“the director”), I am not aware of any circumstance where any other authority has prohibited bicyclists in Arizona.
What about Safety?
As might be expected, there isn’t much in the way of safety data; there was a paper Bicycle – Motor Vehicle Collisions on Controlled Access Highways in Arizona by Richard C. Moeur and Michelle N. Bina covering over 11 years of statewide crash data. There were only 9 incidents (6 injuries, and 3 fatalities) over the entire period. So, in short, any bike-MV collision on a controlled access highway is pretty rare.