GM is using the RelayRides marketplace to make its first major foray into carsharing (Photo: GM)

General Motors is making its first major foray into car sharing through an agreement with RelayRides, a peer-to-peer carsharing marketplace.

The US-based automaker said the two companies would use GM's OnStar onboard telematics system to let GM vehicle owners in the US rent out their cars when they are not using them. The program will launch early next year.

RelayRides provides an online marketplace and offers a $1 million insurance policy to make each transaction safe and convenient.

Once the new program takes effect, RelayRides members renting from GM car owners will be able to unlock those cars with their mobile phones using OnStar. Cars without OnStar will require a small device to provide access to borrowers.

A mobile application on smartphones will allow customers to check for available vehicles, make an online reservation and locate their reserved vehicle via GPS.

"We’re using technology to make both our older and newest models carshare ready and available for those owners who choose to participate in carsharing,” said Stephen Girsky, GM vice chairman.

GM is following other major car companies into the car-sharing market. Daimler, using smart cars,is expanding its car2go program, BMW and car-rental agency Sixt recently announced the start of a new venture, DriveNow, and Ford is developing a sharing scheme with Zipcar.

Founded in June 2010, RelayRides operates in San Francisco and Boston, but plans to grow in other cities.