"We are going to be partnering more and more and more," Google self-driving project chief executive John Krafcik said at a conference held in the shadow of the Detroit Auto Show.
As the project evolves, Google is going to need a 'lot of help' expanding self-driving cars, said Krafcik, a longtime auto executive, most recently at Hyundai.
Major automakers will be able to help it produce "at scale," Krafcik said.
Google has been testing self-driving cars in two US states, California and Texas.
Other automakers, including Audi, BMW, Lexus, Mercedes and Tesla, have also been working on bringing self-driving capacities into vehicles.
The tech giant also sees the technology as critical to addressing deadly car crashes.
Short-term goals include improving the technology's performance in bad weather and in complex traffic scenarios.