NEW YORK (AP) — General Motors Co. and Honda Motor Co. are joining forces to develop hydrogen fuel cell vehicles.

The two companies said Tuesday they plan to develop new hydrogen storage and fuel cell technologies by 2020. They will also push for more hydrogen fueling stations.

Fuel cell vehicles have electric motors that are powered by a chemical reaction between hydrogen and oxygen. The only byproducts are water vapor and heat, so there's no pollution. But the lack of infrastructure to transport and store liquid hydrogen has been a barrier to the cars' development.

GM and Honda already have more than 1,200 fuel cell patents between them, and both companies have experimental vehicle fleets.

Ford, Daimler and Renault-Nissan announced a similar plan to collaborate on hydrogen vehicles earlier this year.