Just thought I would share my "experience" of riding the bus in Mexico.
This was in 1996. I had gone to Mexico around Holy Week to visit my 
youngest son who was in a study abroad program. Since his spring break 
coincided with Holy Week we decided to try to visit Zacatecas (I had 
previously contacted some distant cousins about the possibility of 
meeting them). According to the schedule the trip was to take 8 hours, 
so we decided to take the overnight bus, scheduled to arrive at about 6 
AM. It was a comfortable ride, but we fell asleep - slept through our 
stop (Zacatecas city)- went on two more stops (about 45 min.) then had 
to wait over an hour to catch a bus back to Zacatecas. We didn't dare 
wander away from the bus stop for fear of missing the bus back. We made 
it back OK, 'though the cousins were worried that we had not arrived at 
the appointed time.
The return trip to Mexico City was w/o incident.
 
Natalie Coleman in VA
PS - we had a lovely visit to the city - so much going on due to Holy 
Week, plus a folk festival, with performances in the evening.