I'm looking for vehicle travel data in the USA - at any spatial resolution smaller than the unit of a state, and ideally at a city level. I'm interested in daily, or weekly data and also any information about whether the trip is to work or not.
Two sources that I have previously found are the Texas Transportation Institute Urban Mobility Report, and vehicle miles traveled at a 250m gridcell for Massachusetts from the MAPC link (data is available, but site currently has a problem)
I've looked at the Federal Highway Administration FHWA site which has a special GIS section, but I'm struggling to find data on the site outside of reports in the form of pdfs.
Are there any other sources of data that are available that I have overlooked?