There was a story about this on 11 News last night. The main reason is safety. The new asphalt is a special kind that absorbs water on the road (not that we've had much to speak of lately). This stretch of the beltway was chosen due to the amount of wrecks in this area (I was actually involved in a wreck exiting the beltway to 249 North two months ago but water did not play a part in it).
This asphalt has been used in areas of Austin with some success reducing the number of accidents in those areas although the roads did not hold up that well and required maintenance after a few years. They supposedly have made some adjustments to the asphalt they are putting on the beltway that should make it hold up for 15 years.
Noise reduction was also mentioned on the news but the primary reason was safety.
Here's the link to the story:
http://www.khou.com/topstories/stories/khou090610_tnt_pfc-pavement-toll-road.698724dc.html[This message has been edited by 97porche (edited 6/11/2009 9:50a).]
[This message has been edited by 97porche (edited 6/11/2009 9:51a).]