It's fun the kinds of things you can do with data.
Montreal's transit agencies, including the STM, STL, RTL and AMT, have made their trip data public through a standard called General Transit Feed Specification (GTFS). This allows the data to be sucked into applications like Google Maps, making it easier for people to plan their trips. The time of every stop of every bus is a set data point.
In this video, published a few weeks ago on YouTube, someone has taken this data and created an animation of every bus trip during the average weekday in the Montreal area. STM, STL and RTL buses are represented by little dots that race along their routes.
It's an interesting way to visualize the activity involved in public transit. The animation, which is presented as a 1:600 timelapse (every second represents 10 minutes), starts at 4am with just the night buses on the island of Montreal. After about 6am, it expands into the morning rush hour, and you can see a clear bias toward downtown from all directions. Some thoroughfares like Henri-Bourassa Blvd., Sauvé St., Parc Ave. and Côte des Neiges Rd. emerge as lines because they see so much bus traffic during this time. The traffic dies down a bit after the morning rush hour, though not as much as I expected. After about 3pm there appears to be a general bias away from downtown as the evening rush hour begins. After 7pm, it noticeably dies down, more so after 11pm and 12:30am, and after 2am it's back to just the night buses.
Each of those dots is a bus with a driver in it. Some could have just a few passengers on board, while others could be so packed they're not stopping to pick up more.
It's an expensive system, and a complicated one. But without all those little dots, the city would grind to a halt.
If you're interested in trying to figure out other cool ways of manipulating transit data, you can download the STM's GTFS data yourself. Data from the RTL and STL and AMT are also available. (The AMT data includes commuter trains, its express buses and data from smaller transit agencies like the CIT du Sud Ouest and CIT La Presqu'île.)
UPDATE: The YouTube account in question has done similar things for a bunch of other transit networks, including Boston, New York, Chicago, Los Angeles, Ottawa/Carleton, Vancouver and Toronto (above).
If you want to compare apples to apples in terms of population size, the best match for the Montreal area (whose animation doesn't include many outlying suburbs) would be Seattle: