I do not know the answer to your question. We visit Tucson often (our daughter lives there) & have never seen an ATV driving the streets.
Tucson population is a large city. Lake Havasu City isn't. I would not want to drive an ATV in some of the traffic in Tucson. Although it is easy to get around in Tucson.
Tucson is the 32nd largest city in the U.S.
Tucson's mid-2010 population was 520,116 and the unofficial estimate for 2015 is 589,656. Pima County's 2015, population estimate is 1,132,440.
Total area of Tucson is 227 miles
Elevation is 2,643 ft.
Lake Havasu City had a population of 52,844 (2013).
Tucson is surrounded by five mountain ranges; the Tucson, Santa Catalina, Rincon, Santa Rita, and Tortolita mountain ranges
Tucson is bordered by Catalina State Park, Coronado National Forest, Saguaro National Park East and Saguaro National Park West, and the Tohono O'odham Nation
Tucson is the sunniest city in the United States.
It is a large city but is spread out so much, it never feels like a large city. Very easy to get around the town.
AZ ATV TrailsTucson Area ATV Rides