For most Americans, a self-driving car is a rare sight. Things are different in the Phoenix area.

"I live in Chandler. You see Waymo units all over the damn place," one Redditor wrote. Waymo, Alphabet's self-driving car company, is running trials of a self-driving taxi service in the Phoenix suburb. Cars from Uber are also ubiquitous in the region, residents told Ars, and other companies have cars there, too.

A number of factors have drawn technology companies to the Phoenix area. Phoenix's sunny weather means companies don't have to worry about the complexities of rain, ice, or snow. The region has a lot of wide, well-maintained suburban streets.

The state also has one of the nation's most permissive regulatory environments for self-driving technology. Arizona Governor Doug Ducey signed an executive order in 2015 touting the benefits of self-driving technology and directing state regulators to do whatever they could to promote it.

The result: residents of the Phoenix area now see self-driving cars on a daily basis. Scott Suaso, who lives and works near Chandler, says he sees two or three Waymo cars on a typical 15-minute commute to work.

"When it first started, a lot of people I think were kind of afraid," Suaso told Ars. "That was a year ago. These days, no one really seems to care. Everybody has become so used to seeing them."

Wide suburban streets and nice weather

For at least two years, Waymo's software has been able to drive pretty well on wide, straight suburban roads in nice weather. So it makes sense that Waymo has focused on building a driverless taxi service in the Phoenix metro area, where it's like that almost everywhere and almost all the time.

Phoenix is sunny most days. There are occasional dust storms and rain during monsoon season, Phoenix resident Eric de Gaston told Ars, but otherwise, "we don't have harsh weather at all to deal with."

Smooth seas don't make a good sailor

There's never ice on the roads. Rain is rare. There are hardly any potholes, de Gaston said, because "we don't have conditions that lead to potholes."

The terrain is flat and there are few natural obstacles like rivers or lakes. That, plus the low cost of land, has allowed planners to lay out wide streets in an orderly grid. Plentiful roads and a low population density means that traffic jams are much rarer than in other major metropolitan areas.

"I'm not going to say Phoenix drivers are the best drivers, but the Phoenix metro area is an easy place to drive," de Gaston told us.

De Gaston worried that testing in such a forgiving environment might not serve companies well in the long run. "Smooth seas don't make a good sailor," he told us.

It's a concern that's shared by Kyle Vogt, CEO of the GM-owned self-driving car startup Cruise. In blog post, he touted Cruise's decision to test self-driving cars in San Francisco. "By testing in densely populated areas we expose our software to unusual situations at a much higher rate, which means we can improve our software at a much higher rate" he wrote. Cruise vehicles encounter tricky situations—like having to pass using an opposing lane or navigate through a construction site—20 to 40 times more often in San Francisco than in the Phoenix area, Vogt said.

But Waymo has a huge head start over its competitors when it comes to miles of testing. Regulatory filings showed Waymo logging more than 600,000 miles on California roads in 2016 compared to fewer than 10,000 for Cruise that year. Other companies lagged even further behind.

Waymo's recent buildup in the Phoenix area seems less like a technology development effort than a dress rehearsal for rolling out a commercial product. The company has begun offering rides to ordinary people in the Phoenix area. It signed a deal for Avis to handle vehicle maintenance in the region. And it even launched a publicity campaign in the Phoenix area promoting self-driving technology in early October.

While it makes sense to do testing in challenging places—Waymo recently announced it would do testing in snowy Detroit this winter, for example—it seems sensible to do the first driverless commercial deployment in a forgiving environment to minimize the risk of deadly crashes.

Phoenix is an attractive first market for another reason, too: it has a lot of retirees. A promising market for self-driving cars is people who have become too elderly to drive safely. One of Waymo's partners in its new publicity campaign was Foundation for Senior Living, an Arizona-based organization that provides care to elderly adults.

The Arizona government’s anything-goes approach

Some states have elaborate self-driving car regulations. For example, California's legislature passed self-driving car legislation in 2012, and state officials released 36 pages of draft regulations a few weeks ago.

California regulators have clashed with self-driving car companies. Uber began testing self-driving cars in San Francisco last year, but state regulators objected that Uber hadn't gotten the necessary permits.

Uber eventually got the permits, but the company now does a lot of testing in Arizona, which takes a much more hands-off approach. The Arizona legislature considered legislation in 2012 but it ultimately didn't pass. In 2015, Governor Doug Ducey examined existing Arizona law and concluded that no new legislation was needed to allow self-driving vehicles on Arizona roads. Ducey signed a two-page executive order to woo self-driving cars to the state.

The executive order instructed state regulatory agencies to "undertake any necessary steps to support the testing and operation of self-driving vehicles on public roads." It created an oversight committee to meet periodically and advise policymakers on how to promote the use of self-driving cars in Arizona.

"The group has met just twice in the last year, and found no reason to suggest any new rules or restrictions on autonomous vehicles," the Arizona Republic reported in April.

Ducey's executive order directs universities to set up pilot programs to enable companies to test driving car technology in the state and laid out some fairly basic requirements for those pilot programs. Vehicles must be monitored by a licensed driver, though the monitoring can be done from a remote location. Companies also need to submit proof of insurance or other forms of financial responsibility.

The executive order doesn't address the circumstances for testing self-driving cars independently of universities. It also doesn't lay out any requirements for launching commercial self-driving vehicle services, seeming to cast doubt on whether those are allowed in Arizona.

But Bryant Walker Smith, a legal scholar at the University of South Carolina, believes that's the wrong way to read the law. An executive order can't go overrule state law, and the distinctions Ducey draws—between university sponsored activities and non-sponsored activities, and between testing and commercial use—"don't seem to have a statutory basis," Smith told Ars. In his view, if Arizona law allows testing in a university pilot program, as Ducey believes it does, then it probably allows full-scale commercial deployments as well.

Arizona's Department of Transportation shares Bryant's view. "I'm not aware of any current law that would prohibit" a commercial driverless car service in Arizona, ADOT spokesman Ryan Harding told Ars. "We don't have a problem with that."

In short, Arizona's approach to regulating self-driving cars is to not have any special rules related to self-driving cars.

“They pretty much blend in”

The campaign to attract self-driving car companies to Arizona has been so successful that residents of the Phoenix metro area see the vehicles constantly.

"You see them driving around all over the place," Phoenix resident Eric de Gaston told Ars.

We talked to three different Phoenix area residents, and all three said they saw self-driving vehicles—predominantly from Uber or Waymo—on a daily or near-daily basis. Residents in Chandler, Southeast of Phoenix, reported seeing a lot of Waymo's Chrysler Pacifica minivans that will be used for Waymo's forthcoming autonomous taxi service. Scott Suaso, who lives and works in the Chandler area, told us he's also seen Uber cars and some Intel-branded cars in the Chandler area.

De Gaston, who lives in Phoenix proper, sees a lot of Uber cars as well as earlier-generation Waymo vehicles made by Lexus or Toyota. He rarely sees the Pacifica minivans, which seem to be confined to the area around Chandler.

Uber's vehicles are Volvo XC90s, and they pick up passengers around Scottsdale and Tempe—suburbs East of Phoenix.

Area residents also reported spotting unmarked cars with a variety of sensors and other customized equipment mounted on them, suggesting that a variety of companies were active in the region.

Everyone described the cars as methodical and courteous drivers. "As far as their driving behavior, they pretty much blend in," de Gaston said. "When the light turns green, they're not sitting there texting, so they actually go."

Self-driving cars are cautious drivers, people told us. "Their speed seems to be consistent and deliberate," Suaso told Ars. Waymo cars hit the brakes earlier than a human driver would and slow down more gradually.

Self-driving cars rarely go over the speed limit, even when prevailing speeds are higher. This means they spend most of their time in the right lane on freeways.

One Phoenix resident we talked to found this annoying and wished they'd go a bit faster. Others said it didn't bother them. In fact, they wished human drivers would drive more like the robots.

As self-driving cars have become ubiquitous in the region, the areas motorists have become accustomed to seeing them around. "Everybody has become so used to seeing them that there's almost apathy now," Suaso said.