Popular transit app HopStop today announced the launch of HopStop Live, a crowdsourced platform for reporting and seeing when trains, subways, and buses are delayed. While a couple of apps like NextTrain have tried crowdsourced transit delays before, none have the scale of HopStop: over two million monthly active users, 700 transit agencies, 20,000 lines, and 750,000 stops in total. The free update hits iPhones today, and will land on iPad, Android, and web in the near future. HopStop CEO Joe Meyer says, "It's the biggest product launch in company history."

HopStop Live is inspired by Waze, the GPS navigation service that bundles in alerts for accidents and traffic submitted by users themselves. "Google and Waze brought a lot of transparency and knowledge to drivers around realtime incidences," says Meyer, "and we didn't see Waze going into the transit space." While HopStop Live is inspired by the same principles as Waze, it might not be as useful, since many transit riders are underground when they'd want to report delays. Waze users can report delays within seconds, while many HopStop users (like those riding the subway) might have to wait until they're back above ground to do the same.

Fortunately, the app caches submission you make while offline, and sends them once you're back online — but only if you open the app again. "Once you're off the subway, you'll get walking directions to destinations (using HopStop) so you'll open the app," says Scott Margolis, head of Product Management. "There will be a high success rate for that." It's a hefty request to ask users to provide all the data for a new product, but Meyer's hoping the good word of mouth that got the company this far will keep the train moving. "We've spent $0 on marketing in our entire company history," he says. "Our users have told other users about HopStop, and that's how we continue to grow. They want to see the service get better."

HopStop is far from the best-looking transit app, and provides no push notifications for when your favorite subway goes down, but it's the first app to do crowdsourced transit updates at large scale. The app might not be as vital for subway riders as for drivers, but it's a welcome update in a world where most cities still lack real-time transit information. New York finally got its first real-time transit app a few months ago, but it only works for a few lines. "We can't afford to wait years for transit agencies to slowly make this information available," Meyer says. "We should rely on our user base, the largest transit user base out there."