The US is ahead in the race for a fully self-driving vehicle, according to a report.

Since 2015, Navigant Research, a Boulder, Colorado-based marketing research and consulting company, has rated the 20-or-so companies working on driverless vehicle technology. The most recent report, released January 16, ranked 19 companies on 10 criteria, each of which are linked to a strategy or execution score.

From winner to loser, the companies are labeled as "leaders," "contenders," "challengers" or "followers." All companies evaluated in the report for 2018 fell into the first three categories.

US companies - Google's Waymo, General Motors Co (GM) and Ford Motor Co -make up almost half of the eight leaders (up from four last year), which include BMW-Intel-FCA, Renault-Nissan, Volkswagen and Groupe PSA.

Beijing-based Baidu, which calls itself "China's Google", is in the "contenders" category for its partnership with Beijing Automotive Industry Holding Co (BAIC). Since last year, Baidu has moved up from "challenger" to overtake Tesla and Uber. Six other companies are in this category: Toyota, Jaguar Land Rover, Hyundai Motor Co, Volvo-Autoliv-Ericsson-Zenuity partnership, Navya and Groupe PSA.

Baidu has invested heavily in Apollo, its open-source driverless vehicle software, as it diversifies from internet advertising into artificial intelligence, the Financial Times reported. However, the report notes that "while many companies are looking at the Apollo platform, only China's BAIC has committed to production programs." The company's goal is to have Level 4 driverless vehicles (on a scale of 5 with 0 being no automation) in production by 2021.

Detroit-based GM took first place for its 2016 acquisition of Cruise Automation, its ability to scale up production and its Maven vehicle-sharing service. The report said that the Chevrolet Bolt EV was a "near ideal platform" for electric driverless cars partly because it gives plenty of power for both the vehicle's driverless system and daily operation.

Waymo, the only technology company in the top tier,is in a "dead heat" with GM on the technology front, the report says. The company received high marks for already testing its technology without a safety driver on its fleet of Chrysler Pacifica hybrids in California and Arizona. The company deploys some vehicles on Lyft's platform.

However, Waymo's inability to form a broader long-term manufacturing deal with an original equipment manufacturer (OEM), the report said, is "the single biggest weakness in Waymo's path to success."

Ford has deployed some of its driverless vehicles with Lyft and Domino's Pizza and formed a team focused on developing business models for electrification and automation, the report says. In 2021, Ford plans to launch a Level 4 driverless vehicle.

Of Uber, the San Francisco-based ride hailing company, the report says it has been hit by losses and scandals, including an ongoing trade secret court battle with Waymo that could negatively impact the development of its driverless technology. Uber partners with Volvo and was the first to launch a self-driving taxi fleet in the US. The company has been investing in artificial intelligence and machine learning with the goal of making a fully self-driving vehicle by 2021.

Tesla, the automaker based in Palo Alto, California, is in 19th place - dead last. The report is not optimistic that the company can release a fully self-driving vehicle by 2019 because Tesla has struggled to scale up production.