The companies developing self-driving cars say handing control over to the machines will make the future a far better place. Once robot chauffeurs are here, they say, the number of car crashes will plummet. Liberated from the need to keep our hands on the wheel and eyes on the road, drivers will become riders with more time for working, leisure, and staying in touch with loved ones. We'll free ourselves from the archaic model of the multi-car household. And we won't waste so much space parking the damn things.

Even the NHTSA, hardly a starry-eyed cheerleader for technological progress, says the advent of vehicles that drive themselves will provide "completely new possibilities for improving highway safety, increasing environmental benefits, expanding mobility, and creating new economic opportunities for jobs and investment."

The idyllic picture painted by automakers and regulators may sound overblown, but a new report from consulting firm McKinsey & Company says it is, for the most part, accurate.

Automakers expect to introduce autonomous technology in phases, rolling out the cool new features in otherwise conventional cars. In three to five years, we can expect cars to do the heavy lifting during traffic jams and highway cruising, but cede control to their carbon-based occupants the rest of the time. Beyond that comes the more difficult challenge of driving in urban arenas, where there are far more obstacles and variables, like pedestrians, cyclists, cabbies and the like. That's a tougher nut to crack, but our cars will become increasingly autonomous over the next 25 years, and we can expect them to be fully autonomous by 2040.

Without the need for a human at the helm, one autonomous vehicle could take the place of two conventional/archaic ones.

We're already well on the way. Google's fleet of self-driving cars has logged more than 700,000 miles without causing an accident. Audi let me pilot its sleek prototype from Silicon Valley to Las Vegas earlier this year. And just last week, the bonkers Mercedes-Benz robo-car concept was roaming San Francisco.

The McKinsey report, based on research by McKinsey analysts and interviews with industry experts, buys into this idea of gradual introduction, and divides its findings in three phases. In the first, which runs through 2020 or so, the impact of autonomous technology will be limited: While self-driving vehicles already have infiltrated industrial and controlled settings like farms and mines, passenger vehicles will remain in the prototype and testing phase. This jibes with the timelines laid out by the companies like Mercedes and Nissan, which plan to offer cars with autonomous features by 2020. Audi's shooting for roughly the same date, and while Volvo is targeting 2017 for a large-scale, real-world test involving 100 customers.

The technology will experience growing pains between 2020 and 2035 as the technology begins entering the mainstream. This will require regulators around the world to create comprehensive rules regarding how these cars are developed, tested, approved and licensed. Insurance companies will need to figure out how to change their basic model—drivers pay for individual coverage—to a system where automakers purchase insurance in case of technical failures. Wider adoption of the technology could have ancillary impacts, as well. Independent repair shops will become less relevant, for example, as remote diagnostics and over-the-air updates become commonplace, and fewer accidents—one promised benefit of autonomous technology—could mean fewer repairs. Cabbies and Uber drivers will become irrelevant. So to could long-haul truckers.

Meanwhile, consumers will start to really get accustomed to the idea of giving up the wheel, and they'll probably like it. Safety benefits should come quickly, as precursors to full autonomy have already had an impact: The Insurance Institute for Highway Safety (IIHS) reports a 7 percent reduction in crashes among cars that have a basic forward-collision warning system. Include automatic braking features, and that number is 14 to 15 percent, according to Consumer Reports. More self-driving will mean bigger reductions, which is why autonomous features are a big part of Volvo's plan to eliminate deaths and serious injuries in its cars by 2020.

And given how much time Americans waste in traffic—111 hours annually per driver, per a study by INRIX—that means anyone with one of these cars will be able to significantly boost their productivity.

Beyond 2040

But it’s in Phase 3, after 2040, that the fun begins. This is the point where autonomous cars become our primary means of transport, and all the rules are up for debate. Just as car design will fundamentally change once things like forward-facing seats, mirrors, and pedals are no longer necessary, the way we structure physical space could evolve: McKinsey predicts that by 2050, we might need just 75 percent of the space we now reserve for parking our cars. Because this is America, that means we get back 5.7 billion square meters of space—enough to hold the Grand Canyon and then some. That’s because autonomous cars can pack themselves together tightly (no need to allow space for human to exit).

More than that though, our entire idea of car ownership could change. Currently, cars sit unused about 95 percent of the time. That leaves a lot of room for improvement in terms of how we allocate resources.

We won’t stop buying cars altogether—people will still want the option to “independently drive and use the vehicle, and have fun doing so,” says Kaas— but we will buy fewer cars. Without the need for a human at the helm, one autonomous vehicle could take the place of two conventional vehicles: If Joan is going golfing and Joe needs to go shopping, a single car could drop Joan off at the club, swing back to the house to take Joe to the supermarket and back, then return to the club and get Joan. Kaas also predicts you could see the rise of private commuting services, shuttling customers around for a fee.

The recurring theme in the McKinsey report is that the consumer wins. Yes, cars crammed full of high-end technology will likely cost several thousand dollars more than they do today. But “drivers” will save money in the form of regained time (spend your commute working instead of driving!) and many fewer accidents: McKinsey pegs the savings on repair and health care bills alone at $180 billion in the US, predicting a 90 percent drop in crashes.

The economic boon from increased productivity is harder to quantify and McKinsey doesn't offer a number. After all, there's no guarantee people will use their commute times to work instead of nap, text, or hone their Candy Crush skills. But the general outlook is clear: In a world where we don't drive, we're better off.