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Guiding riders through a storm

How Montreal's STM used Transit's automatic detour detector to reroute riders during a historic ice freeze

April 19, 2023

When an emergency situation suddenly sends service spiralling, it’s all hands on deck for city and transit agency staff to keep people safe. Storms, protests, and other major events can make it all but impossible to keep up with on-the-ground conditions in real time — let alone communicate these updates to riders.

Now, Transit’s automated detour detection helps riders stay informed during emergencies, no agency intervention required. 

A few weeks ago, Montreal faced down its worst ice storm in more than two decades. City streets were strewn with fallen trees and power lines, schools were closed, and more than 1.3 million homes and businesses were without power, many of them for days. 

While crews worked tirelessly to clear branches and get things running, Montreal’s public transit agency, the STM, had one less thing to worry about: communicating pop-up detours to riders in real time.

A month prior, the STM and Transit had launched automated detour detection in Montreal, making it possible to detect and display detours as they happen, integrating the new path and stops into the trip planner — something no other app can do. 

Until now, detour notices (if they even existed) were Babylonian walls of text. With Transit’s automatic detour detector, transit systems can now show detours in real time on the map so riders don’t miss a beat.

What’s more, when Transit updates the line with a detour, we also update the GTFS and send it back to the transit agency, so their website and other communications channels can reflect real-time changes too.

The STM regularly bobs and weaves through road closures and disruptions: on a normal day, more than 1 in 6 bus routes are detoured — a higher number than any other Transit-supported city.

And during this historic ice storm? That number doubled — in the storm’s wake, nearly 1 in 3 lines were detoured. 

Thankfully, with automatic detour detection already in place, Transit was able to lighten the load for our friends at the STM, and give riders a bit of peace of mind when everything else (like when the lights will come back on) felt uncertain. 

Want the full story of how we built the world’s first detour detector? Check out our blog.
Now that we’ve broken the ice? Drop us a line to discuss how we can help storm-proof your city.
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