http://www.cleveland.com/metro/index.ssf/2013/07/odot_confirms_sign_fell_on_another.html
http://www.cleveland.com/metro/index.ssf/2013/06/fallen_sign_on_i-480_bounced_b.html
Shame on ODOT for continuing to use friction clips on overhead signs at all. Many states, including Massachusetts, did away with the practice in the 1980s and require through-bolting instead.