Online TV Guide shows the "Regional Semifinals in Detroit and Houston" starting at 6:00 p.m. CST on CBS for 300 minutes on 3/28.
I'm presuming by the order listed for the two cities, the Detroit game would be played first and that the Houston game would tipoff at about 8:30 CST.
Likewise, it shows on 3/30, "Midwest and South Finals in Detroit and Houston" for 300 minutes starting at 1:00 p.m. So I'm presuming that the Houston regional final would start about 3:30 p.m.
Oh. That's different than what it's been in the past then. They usually wait to see what the matchups are before determining times to make sure there is one marquee matchup per game time for most of the country to see. I know this has been the case for the Elite Eight. Two years ago we didn't know what time the UT/LSU game would be until after UT beat WVU.
For the Sweet 16, there are two games that night, so in Houston they should start around 6:45 and 9:15 Central, give or take a few minutes. I'd be surprised if they've already determined the Elite Eight game in Houston would be at 3:30 because that's not how they've done it in previous years. CBS would much rather have a game like KU/Georgetown as their late game on the 30th than Texas/Memphis or Texas/Pitt.