Photo: Google
The rules for Google’s experimental self-driving cars go into effect on California roads on September 16. Although the company’s self-driving cars have driven more than 1 million kilometers since it began secretly developing them in 2009, they have only been tested once by a government agency on public roads, by Nevada Department of Transportation (DMV) employees in May 2012.
IEEE Spectrum obtained the test drive logs and related emails under the Freedom of Information Act. Some of this information isn’t new. For example, Nevada officials revealed that Google’s self-driving Toyota Prius passed the test almost immediately. But what wasn’t previously disclosed was that Google chose the test route and set restrictions on the road and weather conditions the car could encounter, and that company engineers had to take control of the car twice during the drive.
The world’s first self-driving car test took place in Las Vegas on May 1, 2012. Google had mapped the area and chosen the test route in advance, and the DMV agreed. Chris Urmson, now head of Google’s self-driving car project, was in the driver’s seat in case something went wrong. Next to him was engineer Anthony Lewandowski. In the back seat sat two Nevada state examiners: sportscaster and politician Bruce Breslow, who was then head of the DMV, and Nancy Wojcik, who was in charge of testing and licensing for the state.
The Nevada DMV designed the test to evaluate how self-driving cars perform in common situations. Examiners score Google’s car in every scenario and decide whether it drove fully autonomously, needed Urmson’s assistance, or handed full control over to Urmson. A final checkbox shows what situation the car faced. Here, Breslow recorded the Prius going through four-way stop signs around Las Vegas’ iconic Strip and convention center.
In everyday, smooth traffic conditions, the Prius performed perfectly. Breslow noted that the car detected pedestrians, stopped, and merged smoothly onto the highway up to the local speed limit. At crosswalks, “it’s especially careful. It’s designed for safety,” he said.
Perhaps the cautious pace of Google’s self-driving Prius car began to irritate Breslow. “It was probably overly cautious when approaching traffic lights,” he wrote. Another column noted that Google’s cars were not tested at roundabouts. Similar checks were made at railroad crossings, unpaved roads, school zones and shopping centers. In correspondence with the Nevada DMV prior to the test, Google said it was company policy to prohibit its self-driving cars from crossing unsignalized railroad crossings, instead requiring a human driver to take over. It also said:[Roundabouts are] What makes it especially difficult is that many drivers are unaware of the proper rules in the first place.” In an email to his DMV colleagues, Breslow wrote, “We cannot fail an applicant just because they say they cannot negotiate a roundabout. [sic] Vehicles can’t do that yet.”
What does a Prius do when faced with an unexpected situation? That happened several times during the 14-mile test drive. At one point, a cyclist weaved in front of the car. The car backed up to safely pass the cyclist. The Prius also accurately predicted pedestrians running across the road. But construction sites were trickier. Faced with a partially closed road, the car switched between autonomous and manual modes and braked to a halt, requiring safety driver Urmson to take over. Wojcik didn’t record the situation, but he did record when the driver needed assistance around a curve.
Before the test, Google wrote: “It is difficult to predict whether the proposed demo will encounter several key environmental conditions, including rain, snow/ice, fog, and high winds. Additionally, vehicles do not currently operate in snow, ice, or dense fog.” Fortunately, Google’s driving software outshone the weather forecast: temperatures in Las Vegas in May averaged a scorching 31 °C (88 °F), with almost no chance of rain or fog. Google assured the state of Nevada in writing that its vehicles would handle California rain well and could operate safely around roundabouts and other roadway fixtures that were not considered in the Nevada test.
Following the Las Vegas test, the Prius underwent another performance test in the state capital, Carson City. The DMV Commission then met and approved the first self-driving car test license in the United States. On May 4, 2012, the Prius was issued a special self-driving gold license plate (number AU-001) on a red background. However, Google appears to have made little use of this historic license plate. Most of the company’s testing has been focused in California, and when its Nevada license expired in May 2013, Google did not renew it for at least eight months.
This article was updated on September 11, 2014.
