I don't monitor DART full time, but most of the PD traffic is on 4221 and 4222, which are both encrypted. although I have seen non-PD radios affiliate with those groups as well. I haven't logged traffic on 420x talkgroups in a long time.
Since I now have my mobile rig designed to fit into a backpack, I'll set up the monitoring post the week after thanksgiving when I'm in my office near 75 and Knox and let it capture an entire day (I just did that with the new Parkland system and Baylor Hospital's Dallas campus last week).