If the Governor signs it, the law just gets tougher for those arrested for DUI or Physical Control in Seattle or anywhere in Washington State. The added cost to each person arrested could be between $250 - $600 in Towing and Impound fees depending on where you live in Washington. Not to mention all the constitutional legal issues this law raises. I can foresee this law being challenged on those grounds by Washington State DUI and criminal defense attorneys.
See Bill as passed by Legislature: http://apps.leg.wa.gov/documents/billdocs/2011-12/Pdf/Bills/Senate%20Passed%20Legislature/5000-S2.PL.pdf