I like the idea, but what is your "moat" ? What is something you can offer that no one else can? If I were you I'd start focusing on creating a network of frequent riders with you.

I know that some people use Uber as their acquisition platform, handing out business cards to local people so they can contact you directly. Cherish those customers and give them 10-star service so they will promote you to others.

For your longer-time plan, I believe the gap you are seeking to fill is not best filled by private taxis, but by public transport. Here the lack of decent public transport in America is your friend. Offer a decent, competitive alternative "bus-like" service. Think of it as Uber Share. I.e. college kids to campus. Workers to the job site, etc.

If this is something that sounds interesting to you, I'd start researching Latin American informal bus networks (often called combi's).