| Business | Phone |
| Catalina Engineering Inc 33 N Stone Ave # 800, Tucson 85701 | (520) 544-4067 |
| Entranco Engineers Inc 1860 E River Rd # 300, Tucson 85718 | (520) 299-8700 |
| Paul F Steiner Traffic Engr 4825 W Kay T Dr, Tucson 85745 | (520) 743-9966 |
| Mathieu Engineering Corp 5960 E 2nd St, Tucson 85711 | (520) 747-1133 |