James Martin/CNET

A new Uber feature that lets riders "discreetly" report their driver if they feel unsafe or uncomfortable went live in the US and Canada on Wednesday. Drivers say it's already creating an unfair system for them.

The new feature is meant for nonemergency incidents that make passengers feel unsafe. Uber uses "harsh braking," "inappropriate remarks" and "my driver doesn't have a phone mount" as examples. (The ride-hailing giant has a separate 911 button that passengers can use in the event of an emergency.)

Once riders report nonemergency incidents, a member of Uber's safety team will follow up with the driver.

Some drivers worry the feature could lead to passengers reporting misunderstandings that in turn cause dings to their records. Drivers are also concerned that passengers might take advantage of the system -- exaggerating complaints or making them up -- if they think Uber will offer discounts for rides they're unhappy with. Uber didn't answer a question about discounts when asked by CNET.

Read more: The best dashcams in 2020

"I think it's important for riders to be able to provide feedback on their drivers, but it should happen after the ride, and Uber needs to do a much better job at educating drivers on how this feedback is used," said Harry Campbell, a Los Angeles-based ride-hail driver who runs the popular Rideshare Guy blog. "I think this feature has the potential for a lot of abuse from riders."

With its new tool, Uber is aiming to address safety concerns that've plagued its platform. Over the past few years, hundreds of passengers and drivers have come forward alleging sexual assault and other abuses during rides. Several lawsuits have been brought against Uber by people saying they were raped, kidnapped or groped by drivers. Similar allegations have been made against Uber rival Lyft, which has been sued by at least 56 women since August alleging sexual assault by drivers.

Uber said the on-trip reporting feature will eliminate barriers to reporting nonemergency situations and lets passengers say something when an incident is "top of mind." An Uber spokeswoman told CNET the company will wait until after a trip ends to review a report and follow up with the driver. When reaching out to drivers, the spokeswoman said, Uber won't disclose which passenger made the complaint.

"Our research shows that riders may not consistently report experiences that make them feel uncomfortable or nervous due in part to being distracted after the trip," Tracey Breeden, Uber's head of women's safety, wrote in a blog post Wednesday. "Every piece of feedback we receive can help make the platform safer for everyone."

Sergio Avedian, a Los Angeles-based driver and senior contributor to the Rideshare Guy blog, tweeted a conversation he had with Uber's safety team after a passenger complained using the new tool. The correspondence shows the rider was concerned with "traffic maneuvers and phone use." Avedian responded to Uber by saying he's completed over 3,000 trips and has a 4.93 rating and to stop bothering him with "fraudulent passenger feedback."

"Uber never listens to the driver's side of the story," Avedian said.

On Twitter, Reddit and Facebook, several drivers posted comments saying this new tool puts the onus on them to prove they're driving safely and courteously. Many said it's now important to set up dashcams to make sure they're covered when disputes arise.

Bryant Greening, an attorney with LegalRideshare, which represents both riders and drivers in accident and injury claims, said he commends Uber for working to make rides safer. But he also sees the potential for the on-trip reporting feature to be misused.

"Already targets of rampant false accusations, and resulting deactivations, drivers are concerned that passengers will abuse this tool to score free rides or retaliate for petty disagreements," Greening said. "We're hopeful that Uber will fairly implement its reporting system, which includes due process for accused drivers."