The Cal Poly campus itself is very very safe. I attended there for many years we had very little incidents and it is the largest college campus in all of Calif. surrounded by farmland, rolling hills, and agriculture so it is very isolated and well looked after by the campus police. I always felt incredibly safe on campus, walking/jogging at night was never a problem. Some of the surrounding areas are iffy but they are a bit of a distance away. Certain areas around the campus are very nice neighborhoods depending on the direction you travel. There has been a big restoration push in Pomona in the historic areas over the past 10 years but there are still some shady areas. I grew up in Pomona at a time when it was heavily gang infested. My family moved to Rancho Cucamonga to get away from some of it but it seems to have turned around a bit. Tough to tell unless you drive through at night though!