If your daily commute includes a bus ride then chances are you've been late a few times this past month. Mostly it's just a few minutes here or there, and other times the bus just doesn't show up all together.
Well the reason is simple, there just aren't enough buses on the road as there needs to be.
The STM claims that this is due to many different factors and the problem will take a lot of time to resolve. One of the problems is that some of the workshops where the buses get their maintenance checks are under construction. There is also a staff shortage and many of the buses are having issues and breaking down more often (Even the newer ones). Not to mention all the construction going on right now.
All this means that the STM isn't putting enough buses on the road to handle the current schedule. But the weird part is that they're not going to update the schedules which means your bus is just going to keep showing up late.