Driverless vehicles have the potential to transform the transportation industry by making driving safer than ever before and creating new business opportunities at the same time. Intel estimates that the revenue from driverless vehicles and the new businesses that spring up because of them will generate a massive $7 trillion "passenger economy" over the next three decades.

Of course, there aren't many driverless vehicles on the roads right now, but that's about to change. In 2021, there will be an estimated 51,000 driverless vehicles sold annually worldwide, and that figure will increase to 33 million driverless vehicles sold annually in 2040.

To help investors tap into this massive opportunity, we reached out to three Motley Fool contributors for some ideas on driverless car stocks to keep an eye on. They came back with BlackBerry (NYSE:BB), Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL), and General Motors (NYSE:GM). Read on to find out why.

Woman sitting in driver's seat of car looking at her phone.

Image source: Getty Images.

BlackBerry -- yes, that BlackBerry

Jamal Carnette, CFA (BlackBerry): BlackBerry is the ultimate misperception play. While most retail investors are aware of the company's smartphone story -- more aptly, nightmare -- fewer are aware of CEO John Chen's plans to return the company to top-line growth, which is heavily tied to the autonomous car market.

Last quarter's year-over-year revenue contraction of 9% might appear steep, but when compared to last-year's corresponding-quarter drop of 41%, you can see signs of improvement. Even better, BlackBerry's recent quarter was somewhat of a tipping point, as the smartphone legacy business -- handheld and service access fees -- will be less of a drag on revenue growth moving forward.

During the quarter, the BlackBerry Technology Solutions group saw its revenue increase 31% over the prior year due to its QNX services in the car market. In June, BlackBerry announced QNX is in nearly 120 million cars. While only a fraction of those are fully autonomous, the company has an existing relationship, providing the first-step critical advanced driver-assistance and handsfree systems.

If you're convinced autonomous vehicles will be a huge growth area, it's likely BlackBerry will participate. Turnaround-oriented investors should put this stock on their watchlist.

The original

Danny Vena (Alphabet): When it comes to driverless cars, there's Waymo, then there's everyone else. That's not to say there aren't worthy competitors making progress in the space, but Google's moonshot project -- now Waymo -- was among the first to begin developing autonomous vehicles, and thus far, no other company has demonstrated superior technology.

Waymo previously announced plans to launch a self-driving taxi service by year end and will be adding as many as 82,000 vehicles to its fleet in the coming years. After a year of testing its Early Rider Program, this critical next step could begin generating revenue that could eventually achieve massive scale and be replicated in cities across the country.

At least one analyst believes investors don't fully appreciate the potential represented by Waymo's ride-hailing service. Brian Nowak of Morgan Stanley recently raised its price target for Alphabet to $1,515 -- nearly 30% higher than the tech giant's price today -- citing the ride-hailing launch "as a potential catalyst for value realization." Nowak went on to say, "We believe the current Alphabet valuation ascribes little value for Waymo." 

The analyst went even further, saying that while Morgan Stanley currently values Waymo at about $45 billion, their research suggests that those estimates could be wildly conservative and that the segment could be worth as much as $175 billion when factoring in ride sharing, logistics, and licensing. That assessment has increased from the $140 billion the analyst assigned last year -- an increase of 25%.

When Waymo's ride-hailing service goes live -- and it could happen at any time -- it will represent a big upside for Alphabet -- and for investors.

Don't discount this automaker

Chris Neiger (General Motors): Investors who are looking for a great way to invest in the growing driverless car opportunity -- and bet on a company that knows a thing or to about the auto industry -- need to consider General Motors.

Nearly all of the press attention about autonomous vehicles goes to tech companies these days; meanwhile, GM CEO Mary Barra is leading her 125-year-old company to the front of the driverless vehicle market through its 2016 purchase of self-driving tech company Cruise Automation. Cruise created the artificial intelligence software that enables vehicles to drive themselves, and GM has since used the tech to begin mass producing self-driving cars based on its Chevrolet Bolt.

The company has more than 100 autonomous vehicles that are currently being tested on public roads, and GM's goal is to release a fully self-driving car -- sans steering wheel and pedals -- sometime next year. The vehicle will be called the Cruise AV and will be used for an autonomous-vehicle ride-sharing business starting next year.

The benefit for GM and its investors is that the automaker has the vehicle production and transportation industry experience that many of its rivals can only dream of having. GM is bringing that experience to its Cruise technology and could build a dominant position in the self-driving space as a result. The company could use its self-driving fleet in partnership with Lyft (in which it has a $500 million stake) or go its own way by using the cars in its current ride-sharing company, Maven. Either way, GM is ideally positioned to benefit as the self-driving market takes shape.