As a resident of Austin, TX and a frequent business traveler I have become intimately familiar with Austin Bergstrom International Airport (ABIA) and the TSA security. Here is what you need to know about the 3 security entries.
If you are flying Delta, go to the left two TSAPre Check lines.
If you are flying anything else go to the Center security check point. This has 1 or 2 (during rush) TSAPre Check lines. The line on the left has a shorter lead up belt but tends to go faster.
AVOID: the right side security check point. This does NOT have a TSAPre Check line. They will give you a card but you still need to take out your liquids and electronics. Which is slow but what is really slow is the fact you are in regular lines with pleasure travelers which means delays. This is closest security line for united but you will end up in line for 50% more time every time.