East towards San Cristóbal de las Casas
There's a tollbooth just outside of town. For 6 pesos, you can get a combi to let you out on the highway about 800m from it where there's a pedestrian bridge.
The Conejo bus (6 pesos, but they don't give change) with destination "Carreta" ends at the entrance to the highway. In July 2013, there was a police checkpoint just past the roundabout.