From AASHTO's Top 10:
"8) Adopting Social Media to Provide the Latest Traffic and Travel Information
Eighty percent of state departments of transportation are now using Twitter as well as an array of other "social media" to release information on traffic incidents, road closings, weather emergencies and other transportation-related information. Thousands of travelers have signed up to use this service. In Mississippi, Twitter sites have been set up to guide drivers through hurricane evacuations."