June 20 (UPI) -- Uber customers can tip their drivers on their mobile devices starting Tuesday in some U.S. cities.
The ride-hailing company, in an email to its contractors, said riders in Seattle, Minneapolis and Houston now have the option and the rest of the country will follow by the end of July.
The tipping option hadn't been available on the Uber app but drivers could accept cash gratuities.
Uber said it is developing a 180-day plan to make driving "more flexible and less stressful." Other planned changes include paying drivers if their rider cancels after two minutes or more, compensating drivers who have to wait more than two minutes for their rider and a $2 bump to the base fare for teen riders. Uber has also set up optional injury protection insurance and increased the per-mile rate to help make up for the cost.
Many complaints among drivers have concerned lack of tipping on the Uber app. Rival Lyft already has the option.
Uber CEO Travis Kalanick has previously had a "principled" opposition to tipping because it reduces wages as done by restaurants and taxicab companies.
Kalanick announced June 13 he's on leave from the company to grieve the loss of his mother in a boating accident last month.
He earlier posted on Uber's website that he needed to "fundamentally change as a leader and grow up" after video surfaced of him arguing with an Uber driver.
Kalanick's announcement came before Uber held a staff meeting to discuss recommendations from a months-long investigation by former U.S. Attorney General Eric Holder involving operation at its headquarters, including sexual harassment.
Several executives and board members have recently departed from the company.
"I look at Uber as a workplace culture that has failed. So now we know, working at Uber is not always pleasant," Kate Bischoff of tHRive Law & Consulting told CNBC. "It's difficult, it seems to have this bro' culture. Each one of these individual cases now looks more credible. So yeah, if they are treating drivers poorly, there's a natural human response to take that seriously."