Uber has been testing a secret safety hotline, but it wasn't available in Kalamazoo

There's a secret way to get in touch with Uber in an emergency.

Since late last fall, Uber has been testing a critical response hotline in the 22 cities across the US for passengers or drivers to call in an emergency.

Riders or drivers who dial 800-353-8237 (UBER) will be put directly in touch with a customer support representative on the phone. If it's a true emergency, the call will be transferred to 911.

The secret safety hotline comes to light after an Uber driver allegedly shot eight people, six fatally.

In the case of the Kalamazoo, Michigan, shooting, an Uber passenger called 911 to alert them to the driver and filed a written complaint in Uber's system.

While the written complaint wasn't immediately classified as violent or urgent, the option of a hotline could have theoretically led the passenger to place a call to Uber, much like they had already done to 911.

The hotline gives the passenger the power to determine what is critical, and not just rely on Uber's system as it stands today.

Uber believes that 911 is the best option for passengers or drivers to call in an emergency.

Panic button

"In the United States, 911 is the panic button and it's the panic button that we want people to use," Uber's Chief Security Officer Joe Sullivan said in a press conference following the shootings. "It's the panic button that law enforcement wants people to use. And we don't want to try and replace that."

The company confirmed to Business Insider that Kalamazoo was not one of the cities included in the test.

The pilot program debuted in these 22 cities simply added an option in the Help menu. When looking to report an incident, riders or drivers would click report an issue before seeing an option for the Critical Safety Response Line.

For those not in the pilot zone, including Kalamazoo, the number to contact Uber isn't shown in the app at all.

In the aftermath of the shooting, Uber did not acknowledge the four-month-old safety hotline, despite news site Quartz reporting that they had tried to get in touch. On Wednesday, Uber told Inc that it didn't have a national driver hotline, although later clarified its statement to acknowledge this one that's been in testing.

While it's still considered a "pilot", the number can be dialed by anyone in trouble - whether it's readily available in your app or not. During this trial period, Uber has trained staff in Chicago and Phoenix to handle the influx. The hotline, though, is only to be used for emergency safety situations, like someone leaving behind an insulin pump in the car, versus someone forgetting a jacket or complaining about a long route.

"We are always looking for ways to improve communication with riders and drivers," Uber told Business Insider. "In select U.S. cities, we have a pilot program where riders and drivers can call an Uber support representative directly for assistance with an urgent situation after a trip."