"In a new pilot program in San Francisco, a small percentage of new UberX drivers will pay a 30% commission on their first 20 rides in a week, 25% on their next 20 rides, and then 20% on any rides beyond that. Uber is also testing the same commission in San Diego, except that the tiers are for the first 15 and next 15 rides in a week.
The tiered structure, which Uber began testing in April, will hit new, part-time drivers the hardest…" —Forbes