I'm in Austin this morning, covering the monthly meeting of the Texas Transportation Commission, and a proposal to raise speed limits in some rural areas (none in Dallas-Fort Worth) is on the agenda. I'm guessing the five commissioners will want to speak about the importance of studying the safety issues surrounding the proposed 85 mph speeds. On parts of Interstates 10 and 20 in far west Texas, the maximum speed limit is already 80 mph, so 5 extra miles per hour doesn't seem like much of a leap. But also keep in mind that the state recently did away with separate speed limits for trucks. So, in many of these corridors trucks may no longer be restricted to 65 mph while smaller vehicles are allowed to go faster. Whether it's trucks or economy cars or even Ferraris, how fast is too fast?