Uber and Lyft drivers are desperate for tips. Riders don't shell out, but they'll tip three times as often for food delivery.

• Uber and Lyft drivers often struggle with low or infrequent tips, which many rely on to pay bills.
• Ride-hailing drivers earn below minimum wage in major cities, even with tips, UC Berkeley found.
• Delivery drivers often receive higher or more frequent tips, partly due to American tipping customs.

Chris Yandell, a 35-year-old full-time Uber driver in Oklahoma City, has mixed feelings about his passengers.