The best option in my opinion and experience is to travel in an official caravan from the CIITEV office parking lot to the checkpoint at kilometer 26 (even if you already have a TIP from a consulate or online). The caravan is led by two units of the Tamulipas state police and takes the Colosio route. Another good option is to travel through the city via Av. César López de Lara or Av. Reforma. Taking the Colosio route on your own seems to be more risky (although many do so and don't have any issues). It's also better to not have a large or expensive vehicle and not be carrying much of interest to the criminals.
