The National Transit Database is a fantastic resource for statistics on transit systems in the United States. One of the simpler NTD products is the set of agency profiles produced—in particular, for the top 50 agencies in the country (measured by unlinked trips). I've been interested in transit agencies' use of social media, and Twitter in particular, for some time. So, two days ago, I decided it might make an interesting exercise to look up each of the top 50 agencies, and see who uses Twitter, and who doesn't.

I put the results in a Google Docs spreadsheet; mouse over a Twitter username to see the latest Tweet, or click on the link to view the user on Twitter.

In simple terms, 41 of the top 50 agencies (using data from reporting year 2009) use Twitter. The agencies that do not are:

Of these, I'm most surprised to see that the CTA does not use Twitter. On the whole, though, I'd say the results are tentatively encouraging. I did not perform a detailed assessment to try to judge meaningful use; all I was looking for was whether an agency had an official presence on Twitter. It's entirely possible that some of these agencies, despite having a Twitter account, do not use it to alert riders to disruptions in real-time, or do not respond to Tweets from riders. Many of the agencies, though, do seem to use Twitter as a real-time, two-way channel (as it's intended to be used), and that's a great step forward in terms of passenger communications.