Most of the larger truck fleets out there have not yet. Mainly the problem has been the down time it takes to install the apu's in a truck. On top of the initial downtime, if the apu breaks who is certified to fix it? Once again, more downtime.
I have been hearing lately that Willis APU is giving training on installation and maintanence (to keep warranty) on their apu's to fleets on qualified purchases--this should speed things up a bit. I'm sure Rigmaster and others will follow this model. There is a nice article on the subject
http://www.truckinginfo.com/news/new...category_id=14.