looking for case studies on wins in Dui trials..
If your are looking for information on how many cases were filed in a certain area, you can check www.courts.wa.gov. You may also just call the local district/municipal court for the specific location you're investigating.
On the other hand, if you are trying to find in-depth information about an individual case, you'll likely want to talk to the prosecuting and/or defense attorneys who handled the case. Hope that helps.