ARS 28-701 prohibits a person from driving on the highway at an unreasonable speed. An unreasonable speed might be one that is too high above the speed limit, one that is too high because some hazard exists, or one that causes an accident or puts the life of others in danger.
While not a direct offense in the state of Arizona, not maintaining a reasonable and prudent speed could result in other misdemeanors or infractions. If you are driving faster than 15 miles per hour (mph) when approaching a school crossing, 25 mph when driving through a business or residential district, or 60 mph in other areas such as highways, then you could be deemed as not maintaining reasonable speed.
If your speeds are excessive, it is likely you will be pulled over for speeding, which in Arizona is classified as a class 3 misdemeanor, resulting in a maximum of 30 days in jail or a fine of up to $500.