GM is working hard to develop an autonomous vehicle.

General Motors is ramping up its driverless car efforts in California. Over the last three-months, the Detroit-based automakers says it has more than doubled its autonomous test fleet in The Golden State.GM's autonomous division, Cruise Automation, had a test fleet of around 40 driverless cars just a few months ago, but that count now stands at 100. Cruise Automation is hoping to use its autonomous technology to launch a robotic taxi service within the next year or two.

However, the road to autonomous vehicles hasn't been a smooth one. In September alone autonomous vehicles being operated by Cruise Automation in California were involved in six minor crashes. But according to state records, all six incidents, which included one run-in with an intoxicated bicyclist, were the fault of the other driver.

"While we look forward to the day when autonomous vehicles are commonplace, the streets we drive on today are not so simple, and we will continue to learn how humans drive and improve how we share the road together," GM told Reuters in a statement.

GM is working toward a mass-produced autonomous vehicle but has not yet announced a specific launch date for retail sales.