When interviewing drivers, I found that they experienced stronger, more authentic gratitude when they connected with riders on a personal level. Multiple drivers also repeated the sentiment of "I want passengers to see me as a human, not a service."
Some drivers drive for their families, some do it to support interesting artistic or entrepreneurial work, but they all have a story. Displaying parts of their lives, such as a photo of their child, or sticker of their band in the car could help spark meaningful conversation and connection that enables a deeper level of gratitude.
The idea is also simple, cheap, scalable, and easy to test.