From the front page of the LA Times web page, an article on traffic counts!: L.A. doesn't save data on traffic growth
"But although the sensors and computers collect massive amounts of data about traffic patterns and congestion, they do little to help engineers plan for the city's growing transportation needs -- or determine how development is affecting traffic.
That's because the city does not save the information for more than a few days, using it only to direct traffic in real time by adjusting the speed at which lights turn from green to amber to red."
This is true elsewhere (Minneapolis e.g.), and a damn shame. I have been in meetings about this, but people are frugal and the beneficiaries are in different departments/units than those who would do the work.