Since the pay gap is fair (in the sense that it's driven by personal preferences and experience), there are only two reasons to reduce it: 1) if you think it's

Since the pay gap is fair (in the sense that it's driven by personal preferences and experience), there are only two reasons to reduce it: 1) if you think it's going to cost you women drivers and 2) if you think that men are driving dangerously fast. Point 2 is something that Uber actually has enough data to assess and address, but the better motivation would be safety. Reducing the pay gap would be an ancillary benefit. As for point 1, I think the only option is education. Point out that pay increases with experience, and by how much. Maybe draw drivers' attention to more lucrative areas? Though I think that's contingent on experience as well. Beyond that, any attempt to address the pay gap seems unfair and, as fatjokes points out, possibly illegal.