Using Microsoft Streets and Trips 2013 with Windows 8 Professional, I utilize a S&T_POI_Mega File. Simply do a search on your web browser for low clearances and you will find that resources abound for most any type of navigation interest you have.
Its not a bad idea to pick up a copy of Rand McNally's Motor Carriers Atlas Premium edition or you can connect to http://www.aitaonline.com/ where there is a listing by state.
If you came to our neck of the woods, there are entire State Parkways that do not appear in any low clearance list or database, but be assured trucks can be found a number of times a year wedged under a 7'2" clearance overpass here.
Its never a bad idea to obtain local knowledge before you journey out. Most importantly, be vigilant for any road signs indicating low clearances or other upcoming road restrictions or hazards.
Safe journeys.