Yeah, the witness description of the crash via the NYT (hitting concrete barrier, flying high up in the air, THEN exploding) makes me think this was someone engaging in illegal activity such as drug running or "making a run for the border" who got freaked out at being flagged for an inspection, hit the gas and try to "gun it" through the checkpoints. Very curious to hear more, but coupled with no evidence of explosives in the vehicle, this does not seem to match with terrorism or a planned explosion.