I don't think you would ever get any useful answers on this. Every hospital I've ever worked at considers this proprietary info. Their concern is that a high average wait time will result in patients not wanting to go there so they are pretty guarded about it. The exceptions are the places with low wait times or one of those "Dominos ED" programs where they promis 30 minutes or less. If you just look at those you'll be biased toward shorter than actual times.
The other question is what time are you asking for? Time to triage, time to room, time to doctor, time to dispo, time to EKG and CT for the MIs and CVAs, all of those are different and really have different meanings about how the ED functions.
Interestingly the hospitals do know these times, especially if they have EMR and/or stroke and chest pain centers. They just don't tell anyone unless it's in their best interest.