Covered in If it could all be so effective as this, Dave covers how the information is shared with the public - much in real-time - via Commuterlink.
It can the be reused by other websites such as Hello Salt Lake City.
With traffic being a key concern for residents of most big cities, and given the success of the Australian Bureau of Meteorology in allowing mash-ups of weather (another big citizen concern), I wonder when we'll see state governments in Australia allowing this form of use of their traffic data.
As Dave concludes, due to allowing community mashups of government data,
The end result is that Utah government data actually has much broader disemmination and utility than just what is presented on the state's website. With hundreds of information systems, there are many more examples where this kind of sharing could be valuable, but it doesn't happen. It's a big opportunity.