Buses stuck on the 520 Bridge. Photo via Mike Koss.

We've been hearing horror stories all night of Seattle area commuters who've been stuck in traffic for hours as an unusual November snowstorm hit the Puget Sound area. The icy roads caused plenty of havoc on the roadways, but the storm also rendered one of Seattle's most popular transportation-related iPhone applications virtually useless.

OneBusAway, which displays real-time information for King County Metro bus routes, was not able to display accurate bus arrival and departure times today after King County shut off the data feed that tracks bus locations.

It may seem counter-intuitive to shut off a feed during a big storm, a time when bus riders rely on accurate transportation information to safely get from point A to point B. But Brian Ferris, creator of the OneBusAway app, says that the tracking technologies don't work properly when buses are moved onto alternative routes.

"Why would they pull the real-time feed in conditions where you'd probably agree that it would be extra useful?" Ferris writes in a blog post. "They do so because the current tracking system for King County Metro buses doesn't work well when buses are on adverse weather reroute."

That's an unfortunate scenario for bus riders, some of whom were stranded in the cold hoping that buses were on the way.

"OneBusAway claims that everything's hunky-dory with the 5 and the 358, which sounds implausible. Anyone know for sure?" wrote one Twitter user who was waiting for a bus in Seattle.

In his blog post, Ferris notes that outdated technology on King County buses makes it especially difficult to track bus locations when weather turns nasty.

The position of each bus in Metro KC is not tracked with GPS, but rather with a decidedly lower-tech approach. Each bus is outfitted with a device that can radio the current odometer reading for the bus back to a server. If we know the odometer reading when the bus starts its route, we can periodically monitor the real-time odometer readings to determine how far along the route the bus has traveled. This gives us an estimate of position and from there, an estimate of how early or late a bus is. This is how http://mybus.org works and OneBusAway is just a fancy front-end to MyBus.

The problem comes with buses on adverse weather reroute, or any type of temporary reroute. When a bus goes on reroute, the physical route changes and the odometry calculation based on the original route used above is no longer accurate. In a perfect world, we would know when a bus is on reroute and adjust to its new route. Unfortunately, there is currently no automated way for handling this situation.

Of course, the problem could easily be resolved by tracking buses with GPS systems. But in an email to TechFlash, Ferris said a GPS bus tracking system is probably at least two years away from being implemented.

"Realistically, we're still years from a solution that can give you an accurate picture of the transit network looks like in conditions like these," Ferris wrote.

In the meantime, Ferris said he's working on real-time, machine readable service alerts about cancellations, detours and delay which can be delivered to devices in "smart ways."

And, in a follow-up blog post titled "The Snow Came Too Soon," Ferris writes that he's been working with King County Metro over the past two months to get adverse weather routes placed in the app.

"The good news is that we are making a lot of progress, but the bad and somewhat obvious news is that I didn't finish in time," Ferris writes.

[Twitpic photo via Mike Koss]