 Pro One welcomes past customers of Sierra Diesel for diesel smog test. The corner of Mill and Terminal in Reno. Home of the no-appointment-needed diesel smog inspection. Pro One Automotive. Beautiful morning to walk the dog. Beautiful morning for traffic. Things flowing well. Not so much last night. A five-car collision involving a rollover involving five cars at Sun Valley and East 2nd. Kept things closed on Sun Valley for the month of June.