In 2013, Google bought Waze. Which was a popular navigation app, and one of the major things that it had over Google Maps, was the ability for drivers to report construction and accidents. This helps other drivers avoid certain areas, so they aren't stuck sitting in traffic. Since acquiring the company, Google has kept the app and service going, while also integrating some of its features into Google Maps. Now, Google is launching a carpooling service with Waze. Which it initially launched in Israel last year - known as 'RideWith' then later renamed to 'Waze Rider'. Now they are expanding the service into the US, starting with Silicon Valley.
The service is a bit different from Lyft and Uber, who also call San Francisco "home". Seeing as Lyft and Uber are more about ride sharing, and having drivers drive people to where they want to go and Waze Rider is here to carpool drivers together. Seemingly to get more cars off of the road and hopefully improve traffic conditions. Right now, Waze is targeting companies in San Francisco, so that drivers can ride together to work, seeing as they do work at the same company. According to SFGate, the testing in San Francisco is starting with about 25,000 employees from select companies, that will use the service to get to and from work each day.
While this hasn't been made public, it seems that Alphabet will be using Waze to do their own ride-sharing with autonomous cars in the next few years. Google has been at the forefront of the autonomous vehicle industry and have been testing in a few different cities in the US already. They have mentioned that they want to have their own ride-sharing program, which would eliminate the need for many to buy cars these days.
Waze Rider, which is only in San Francisco and Israel right now, will likely head to other parts of the country and other countries in the near future. Like Lyft and Uber when they first got their feet wet, expansion is going to take some time. Even for a company as big as Google.