Originally Posted by
txvintage
TT set ups are for riding more in solo, or at least crowded, situations. Being that far forward is certainly more comfy, and "aero", but the handling is not as stable as traditional drop bars, riding the hoods, or on the bar.
In racing, you are not allowed to use Aero bars in a road race or crit by USAC or UCI rules. The rules does not exist to prevent someone from gaining an advantage, but rather to protect the peleton or the pack.
If you find that you really enjoy using aero bars, there are clip ons that you use and remove if need be.
I have clip on aerobars on my bike and agree with Txvintage. Additionally, since the brake levers are usually found on the bar (not the aero bar) there is no immediate access to the brakes in an emergency. In a group ride situation, it is very easy to collide with other riders when in the aero position (no brakes.) The group rides that I have been on permit aerobars (do not require removal) for the ride but prohibit their use for the above mentioned reasons.