: While driving through the middle of nowhere, I picked up KNBR, AM 1070,
: a clear-channel station based in Los Angeles. They had an ad 
: claiming that they were able to get traffic flow information from 
: all of the thousands of traffic sensors that CalTrans has placed
: under the pavement. Does CalTrans sell this info? Does KNBR have
: an exclusive? What's the deal?

: ==Doug "Former L.A. commuter" Claar

You were right the second time, it is KNX. Believe it or not, I also
listen to KNX in the evenings here in Colorado! It's kind of fun driving
through the country listening to traffic jams on the 405. Back to your
original question. Yes, there are sensors just past every on-ramp and
off-ramp on the freeways. They're the same sensors used at most stoplights
now (coils in the pavement). You might want to give CalTrans a call or
even ask Bill Keene (KNX's traffic reporter). I doubt if just anyone can
get the information, but it would be worth asking just in case you can
get it.