Pretty common across the country I'll bet. I recently drove from Punta Gorda Florida to Dixon Illinois. Had the radio scanning with carrier squelch all the while, and heard a LOT of construction crews using FRS radios. Just my impression, but I think every construction zone I came across had people using FRS radios, at least where there were workers visible.
I also heard some fellow travelers using FRS to communicate while 'caravanning'. That came in pretty helpful a couple times when lanes were blocked due to construction/accidents. I was able to get into the best lane well ahead of time since they were ahead of me and I overheard their complaints. Which segues into CB...
I monitored CB channels 9 and 19 on a separate radio, in order to hopefully be forewarned of traffic issues... but I never heard a peep the entire trip. I thought maybe I had a problem with the radio or antenna, but when I got to Illinois I had a friend key up his CB, and it sounded fine. I guess CB is truly dead. As an aside, I monitor 9 and 19 at home as well, and very rarely hear any traffic.
I did also hear a lot of GMRS traffic on the trip. Mostly it was agricultural related, some of it was just chewing the fat. Interestingly, the only 'proper' GMRS traffic I heard was in Northern Georgia, where two guys discussing the weather and their plans to replace some coax gave their call signs properly. Otherwise the only call signs I heard were from a few repeaters automatically ID'ing.
And finally, I also monitored the MURS channels, mostly out of simple curiosity. Passing through the countryside, I heard a lot of data traffic in heavy agricultural areas, 'cotton country' and 'corn country'. In metro areas there was some light traffic from 'BigBox' stores.