Smart Signs Help Crashes, But Not Travel Times
From The Seattle Times:
http://seattletimes.nwsource.com/html/localnews/2013373837_smartsigns08m.html
While the commute into downtown Seattle is still slow, the amount of accidents appears to have gone down. Which is the real purpose of these signs. And again, they have been shown to work in Europe.
More:
http://www.wsdot.wa.gov/smarterhighways/
http://www.pugetsoundtransportation.com/its/
Ben