Uber's ongoing effort to improve relations with its drivers entered a new phase Tuesday, as the company announced additional support for the men and women behind the wheel.

This is the second wave of changes the San Francisco-based company introduced this summer to make driving for Uber more attractive. The first, announced about a month ago, included a long-awaited tipping function added to Uber's app. The latest changes make it easier for drivers to communicate with the company, provide a more measured response to rider complaints, and add a $15 charge to passengers if a driver has to return an item left behind in a car.

In Philadelphia, the two major ride-hailing app companies are Uber and Lyft, and some drivers choose to drive for both. Uber is seeking to make itself the more attractive option for drivers as it competes with Lyft for dominance in Philadelphia and its surrounding suburbs.

"We've always tried to be a driver-focused brand and present flexible income opportunities that never before existed," said Brian Hughes, general manager for the company's Pennsylvania operations. "As we grew so fast, there are times we missed some important details."

There are about 20,000 Uber drivers in the Philadelphia region.

Uber is a poster child for Silicon Valley tech start-ups, but one of its new initiatives is decidedly old school, a phone help center for drivers. Drivers previously had to communicate with Uber either by texting through the app, or visiting an Uber office in person. Drivers' desire to interact with a real person over the phone led to the introduction of driver support operators available at all times, Hughes said. Now live in Philadelphia, drivers can connect with a support person by calling through the app.

Drivers also felt unfairly penalized by passenger complaints, Hughes said. A driver with a years-long record of safe driving could be temporarily suspended from the app after three passenger complaints of dangerous driving, a step that now won't be taken without a review of the driver's history. Drivers also won't be docked points in Uber's rating system if a customer complaint is about an element of the ride a driver can't control, such as a glitch in Uber's app. Uber's rating system determines whether drivers have access to VIP passengers and, alternatively, can lead to penalties if a rating dips too low.

Adding a $15 charge for passengers who need a lost item returned respects the time that takes from the driver's workday, Hughes said. He thinks passengers will accept the extra cost.

"Typically, if you think about the value of a wallet or a cellphone, many riders requested a way to reimburse drivers through the app," he said.

Other improvements Uber is offering drivers include the ability to make appointments to meet with someone at one of the company's support centers and speedier processing time for documents that drivers need to have reviewed before they can pick up riders, Hughes said.

The changes represent a significant financial investment for Uber, though Hughes declined to offer an estimate on the cost to the company.

"Everything really adds up, particularly when you consider the scale of the business," he said. "There actually are some pretty significant investments going into the drivers here."