Where I can find MSA commuter stats? (living in, rail)

[Woodchucker]

If I am correct, I believe counties become part of an MSA when 25% of the population commutes to said MSA. I was wondering how close some CSAs were to becoming an MSA. Does anyone know where you can find up-to-date numbers on commuting.

In particular, I was curious how many people from the Providence, Worcester, and Manchester MSAs commute to the Boston area. Providence and Worcester have commuter rail to Boston, and it seems like many people commute from Manchester and Nashua too. Not only to Boston itself but to suburban areas that have a lot of business, particularly along 128.

After considering this area (which I am most familiar with) I considered other CSAs that are often thought of as semi-cohesive units, such as the Bay Area. What percentage of SF's MSA commutes to SJ's, or vis versa. It seems like a lot of people working in Silicon Valley are now living in San Francisco. How about Baltimore and DC?

I'm just curious whether these CSAs are close to the threshold of being deemed an MSA? Or have the already reached the commuter threshold and are considered separate MSAs for political reasons?

(I imagine most of you are familiar with the terms, but just in case: An MSA, or Metropolitan Statistical Area is what is commonly cited when people talk about "metro areas"- it's the region around one, or a few major cities. A CSA is a Combined Statistical Area and includes nearby metro areas that are influenced by the main MSA. The definitions are primarily based on commuting patterns but also require congressional approval.)

[lammius]

Census Bureau Journey-to-Work data. Have fun and please report back your findings!

Metropolitan and Micropolitan - Other Resources - People and Households - U.S. Census Bureau