I've been informed--and could be corrected--that it's illegal to hitch-hike on the interstates within a hundred miles of Houston, or at least between Houston and Louisiana. Know someone whose friend's motorbike broke down on the highway, and he got arrested for just walking down the shoulder with his pack on his back.
Also, it's illegal to hitch-hike by the road/sidewalk/interstate shoulder near the truck stops east of Dallas. The nearest stops east are in Rockwall County, which prohibits flying signs for money or rides. The cops do enforce this ordinance and do not permit thumb-waving. So just set you and your ride-sign on the bench by the back of the TA (this TA security doesn't care; the local hobo told me not to even bother with the Love's) if you're looking to get out.
If you're looking to head east with a trucker from Dallas and can't get to the Rockwall TA, you can try the onramp by the Fuel City pumps in industrial Dallas. They're a short walk from the light rail, though Fuel City is not an actual truck stop.