How Driverless Cars Will Workby Jamie Page Deaton

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Anti-lock brakes, a standard feature in most cars, are a basic form of driverless technology.

2008 HowStuffWorks

Current Driverless Car Technology

One of the main impetuses behind the call for driverless cars is safety. Because driver inattention and

driver error cause so many accidents each year, it's natural for carmakers to focus their efforts on

systems that can make cars safe, even if drivers aren't. There's a continuum of these "driverless" systems

-- some don't seem driverless at all, and others are on par with science fiction cars.

One of the driverless systems that you may not have realized was driverless is anti-lock brakes. Sounds

surprising, doesn't it? After all, anti-lock brakes need the driver in order to work. Still, they represent one

end of the driverless continuum because anti-lock brakes perform a function that drivers used to have to

do themselves. When a car is braking hard and doesn't have anti-lock brakes, the wheels can lock up,

sending the car into an out-of-control skid. In a car without anti-lock brakes, the driver has to pump

the brake pedal to keep the wheels from locking up. With anti-lock brakes, the system does the pumping

for the driver -- and does it better than the driver. The system can read the wheels and knows when they

are about to lock and react faster and with a more appropriate response than a driver could. Anti-lock

brakes are one of the first technologies that take cars in a driverless direction.

Another type of driverless system is traction or stability control. These systems are so transparent that

usually only professional drivers recognize when they've taken control. Like anti-lock brakes, traction and

stability control react better than a driver ever could. Unlike anti-lock brakes, these systems are very

complicated and use multiple systems within the car to keep the driver from losing control.

Stability and traction control are systems that can detect when a car might go into an out-of-control skid or

roll over and work to prevent that from happening. The systems are constantly reading the car's direction,

speed and how well each wheel is connecting to the road. When it detects the car going out of control or

starting to roll, stability or traction control will step in. Unlike a driver, these systems can apply brakes and

increase or decrease power to individual wheels, which is often better than brakes or power being applied

to all four wheels. When working properly, the system gives just the right response, unlike drivers, who

often over-correct during emergency maneuvers.

Continue reading to learn about the more sci-fi driverless car tech already on the road.

THE DARPA URBAN CHALLENGE

Some of this future driverless car tech may be closer than you think. The DARPA (Defense Advanced

Research Projects Agency) Urban Challenge pits teams against each other to create cars that can

negotiate traffic autonomously. The goal of the program isn't just to reduce traffic accidents and

congestion, however: it's to produce driverless vehicles for combat, keeping soldiers far from the front

lines.

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Cruise control is a basic driverless system. Adaptive cruise control falls closer to the sci-fi end of the spectrum.

Ye Liew/Dreamstime.com

Future Car Technology That's On the Road Today

Now that we've talked about driverless systems that don't seem so driverless, let's look at some that fall a

little bit closer to the sci-fi side of the spectrum. Pre-safe systems are starting to become common in

certain luxury car brands. The systems differ depending on the car, but what all have in common is that

they can anticipate crashes and prepare the car to keep the occupants safe.

Take the example of the rear-end collision from the first page. In a car with a pre-safe system, an alarm

might go off as the driver nears the stopped car. At the same time, the pre-safe system might start

priming the brakes so that just touching the pedal will apply their full force. While all that's going on, the

car will start reducing engine power, which will slow the car and reduce the severity of the crash. Finally, if

the system detects that a crash can't be avoided, it will prepare the airbags for deployment and tighten all

of the seat belts, keeping occupants safe. What's really amazing is that it will do all that in less time than it

takes the driver to slam on the brakes.

Cruise control is another common driverless system that's available in most cars. Cruise control keeps

the car at a constant speed, set by the driver, without the driver constantly having to press the gas pedal.

Cruise control isn't completely driverless, however, because the driver must watch constantly for slower

moving cars in his or her path.

Adaptive cruise control takes care of that. Though it's currently available on only a few cars, it's very

simple. Using radar sensors on the front of the car, adaptive cruise control can tell when an object is in

front of it and, if the object is moving, how fast it's moving. When cruise control is set, adaptive cruise

control will maintain a constant speed, but will also maintain a set distance between it and the car in front

of it. That means that if you set adaptive cruise control at 60 miles per hour and come up on a car going

55 miles per hour, adaptive cruise control will automatically decrease your car's speed and maintain a

safe distance between the two cars.

Want to go even further into the future? Head to the next page to learn about cars that can park

themselves

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Self-parking Cars

It's probably a good guess that if you've damaged a car, it wasn't in a big accident but in a little parking

fender bender. Parking is probably the least dangerous thing people can do in a car, but we still manage

to mess it up anyway. Though some carmakers have put in rearview cameras, sensors that tell drivers

how close they are to surrounding objects -- and even computer generated 360-degree views of the car --

people still manage to scrape, ding and dent their way into parking spaces.

Drivers of the Lexus LS 460 L who opt for the car's Advance Parking Guidance System don't have

those problems, though. The system uses sensors all around the car to guide it into a parallel parking

space (yes, that means the driver takes his or her hands off the wheel and feet off the pedal). Of course,

the system isn't ready for a cameo on "Star Trek" just yet. Before it can work, the driver has to find a

parking space, position the car next to it, and use the in-cabin navigation screen to tell the car where it

should go. Also, the parking space needs to be 6 feet (1.8 meters) longer than the car (and the LS isn't a

short car). Still, the self-parking system is a big achievement in driverless car technology. With it, the car

behaves like a driver might -- reading the area around it, reacting accordingly and going safely from point

A to point B. While it's not the same as sitting back and relaxing while your car drives you home for the

night, it's the first step in that direction.

The next move in driverless car technology may be just around the corner. In fact, some carmakers hope

to have driverless cars on the road by 2018. Read on to find out what technology is needed and how it will

be applied.

DRIVERLESS CARS IN POP CULTURE

The idea of a driverless car is nothing new. From the Batmobile to KITT, cars that can operate on their

own have captured people's imaginations. The technology for bringing theses cars to reality isn't as far off

as you might think.

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Automated Guided Vehicle Systems

We've all heard stories about kids ordogs that accidentally put a parked car in gear, causing an accident.

But have you heard about the frog that can drive your car for you? We're not talking about one of Kermit's

relatives; we're talking about FROG (Free Ranging On Grid) technology. FROG technology is used

in Automated Guided Vehicle Systems, which are, well, driverless cars. The technology is similar to the

self- parking system we discussed on the last page but takes things a little further.

FROG vehicles are equipped with acomputer that contains a map of the area in which the vehicle

operates. The vehicle starts from a known location and uses the map to determine the route to its

destination. It counts wheel revolutions to figure out how far it has traveled (sort of how you might count

steps to figure out how far you've walked). To check itself, the vehicle also uses various calibration points

(electronic landmarks for the vehicle) in the area it works. This technology is already in use at some ports.

FROG vehicles can be loaded with cargo then sent on their own to the unloading area.

FROG can even be used in public transportation hubs. In these cases, passengers go to a stop and push

a button -- just like calling an elevator. When the FROG vehicle arrives, passengers get in and push a

button for their destination -- again, just like in an elevator. Using the on-board computer, map and

calibration points, the FROG vehicle takes the passengers where they want to go.

The problem with FROG technology is that is can be used in only a limited area. Automated highways are

being looked at as a way of extending driverless tech to larger areas. While different scenarios are being

tested, at their core, automated highways would work together with smart cars: cars that have advanced

systems sort of like adaptive cruise control. The highways would be relating information constantly about

speed, road conditions, obstacles and directions to the cars, which would be able to interpret and react to

the information.

In the next section, we'll find out about the ethics of handing over the driver's seat.

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Urban Light Transport is a revolutionary driverless taxicab. It's yet to be seen whether the masses will place trust in driverless cars.

ATS Ltd/BWP Media/Getty Images

Driverless Car Ethics: On-ramps and Speed Bumps

Now, you may be thinking that all this driverless car tech is just around the corner and we're getting ready

to step into a driverless utopia. Some agree with you. General Motors and Carnegie Mellon University

researchers are working together to develop driverless cars and hope to bring one to the market by 2018.

Advocates of driverless car technology point to improved safety (because driver error won't be a factor),

decreased traffic and decreased pollution because of the reduced traffic.

Others aren't convinced. Let's be honest -- people like to drive their cars! Driving can be relaxing and

freeing, and there are still a lot of bugs to work out of driverless car technology before people will be

ready to trust it with their lives. There's also the flip side of driver error: human judgment. Driverless

technology will always make the call that protects the car and the people in it. A driver might make a call

that does more damage to their car, but saves others. For example, say you're on the road when a car in

front of you skids out. There's no time to stop. On the left is a large truck. On the right is a group of

children waiting to cross the street. Most drivers would choose to swerve into the truck to avoid hitting the

pedestrians. Driverless car technology wouldn't necessarily recognize the children -- it would simply see

the path of least resistance and steer the car towards it. It's an extreme example, but issues like this need

to be resolved before we can hop in our car, tell it where to take us, and enjoy the ride.

To learn more about driverless cars and driverless systems, look over the links on the next page.

"I WASN'T SPEEDING, OFFICER. MY CAR WAS."

Another issue that needs to be worked out before driverless cars are widespread is what happens when

the car makes an error. Should a driver be penalized because his or her car malfunctioned?

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Lots More Information

Related HowStuffWorks Articles

How Cruise Control Systems Work

How Anti-Lock Brakes Work

How the New Knight Rider Car Works

How the Batmobile Works

Traction Control Explained

How Flying Cars Will Work

More Great Links

DARPA Urban Challenge

Sources

Ashley, Steven. "Smart Cars and Automated Highways" Mechanical Engineering Magazine. May, 1998.

http://www.memagazine.org/backissues/membersonly/may98/features/smarter/smarter.html

Greene, Kate. "Stanford's New Driverless Car." Technology Review. June 15, 2007.

http://www.technologyreview.com/Infotech/18908/?a=f

Innovative Transportation Technologies. "ParkShuttle."

http://faculty.washington.edu/jbs/itrans/parkshuttle.htm

Krishner, Tom. "GM Researching Driverless Cars." MSNBC. January 6, 2008.

http://www.msnbc.msn.com/id/22529906/

Squatriglia, Chuck. "GM Says Driverless Cars Could Be on the Road by 2018." Wired Magazine. January

7, 2008. http://blog.wired.com/cars/2008/01/gm-says-driverl.html

Strauss, Eric. "CES 2008: A Driverless SUV Gives Tour of the Future." ABC News.

http://abcnews.go.com/Technology/GadgetGuide/story?id=4101838

Tierney, John. "In the Future, Smart People Will Let Their Cars Take Control." The New York Times.

December 4, 2007. http://www.nytimes.com/2007/12/04/science/04tier.html

Trillan, Calvin. "Park, He Said." The New York Times. January 26, 2007.

http://www.nytimes.com/2007/01/26/opinion/26trillin.html

Print

Cite

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Google driverless carFrom Wikipedia, the free encyclopedia

Not to be confused with Google Drive.

Toyota Prius modified to operate as a Google driverless car driving a test course.[1]

The Google driverless car is a project by Google that involves developing technology for autonomous cars.

The project is currently being led by Google engineer Sebastian Thrun, director of the Stanford Artificial

Intelligence Laboratory and co-inventor ofGoogle Street View. Thrun's team at Stanford created the robotic

vehicle Stanley which won the 2005 DARPA Grand Challenge and its US$2 million prize from the United States

Department of Defense.[2] The team developing the system consisted of 15 engineers working for Google,

including Chris Urmson, Mike Montemerlo, and Anthony Levandowski who had worked on the DARPA Grand

and Urban Challenges.[3]

The U.S. state of Nevada passed a law on June 29, 2011 permitting the operation of autonomous cars in

Nevada. Google had been lobbying for robotic car laws.[4][5][6] The Nevada law went into effect on March 1,

2012, and the Nevada Department of Motor Vehicles issued the first license for an autonomous car in May

2012. The license was issued to a Toyota Prius modified with Google's experimental driverless technology.

[7] As of April 2012, Florida became the second state to allow the testing of autonomous cars on public roads.

[8] California became the third state to legalize the use of self-driven cars for testing purposes as of September

2012 when Governor Jerry Brown signed the bill into law at Google HQ in Mountain View.[9]

Contents

  [hide] 

1   Road testing

o 1.1   Incidents

2   Commercialization

3   See also

4   References

5   External links

Road testing[edit]

Lexus RX450h retrofitted as a Google driverless car

The project team has equipped a test fleet of at least ten vehicles, consisting of six Toyota Prius, an Audi TT,

and three Lexus RX450h,[10] each accompanied in the driver's seat by one of a dozen drivers with unblemished

driving records and in the passenger seat by one of Google's engineers. The car has traversed San

Francisco's Lombard Street, famed for its steep hairpin turns and through city traffic. The vehicles have driven

over the Golden Gate Bridge and on the Lake Tahoe.[3] The system drives at the speed limit it has stored on its

maps and maintains its distance from other vehicles using its system of sensors. The system provides an

override that allows a human driver to take control of the car by stepping on the brake or turning the wheel,

similar to cruise control systems already found in many cars today.[2][11]

On March 28, 2012, Google posted a YouTube video showing a Morgan Hill, California resident, Steve Mahan

being taken on a ride in its self-driving Toyota Prius. In the video, Mahan states "Ninety-five percent of my

vision is gone, I'm well past legally blind". In the description of the YouTube video, it is noted that the carefully

programmed route takes him from his home to a drive-through restaurant, then to the dry cleaning shop, and

finally back home.[12][13]

In August 2012, the team announced that they have completed over 300,000 autonomous-driving miles (500

000 km) accident-free, typically have about a dozen cars on the road at any given time, and are starting to test

them with single drivers instead of in pairs.[14] Three U.S. states have passed laws permitting autonomous

cars as of September 2012: Nevada, Florida, and California.[15] A law proposed in Texas would establish criteria

for allowing "autonomous motor vehicles".[16][17]

Incidents[edit]

In August 2011, a human-controlled Google driverless car was involved in the project's first crash near Google

headquarters in Mountain View, CA. Google has stated that the car was being driven manually at the time of

the accident.[18] A previous incident involved a Google driverless car being rear-ended while stopped at a

trafficlight.[19]

Commercialization[edit]

While Google had no immediate plans to commercially develop the system, the company hopes to develop a

business which would market the system and the data behind it to automobile manufacturers. An attorney for

the California Department of Motor Vehicles raised concerns that "The technology is ahead of the law in many

areas," citing state laws that "all presume to have a human being operating the vehicle".[2] According to The

New York Times, policy makers and regulators have argued that new laws will be required if driverless vehicles

are to become a reality because "the technology is now advancing so quickly that it is in danger of outstripping

existing law, some of which dates back to the era of horse-drawn carriages".[6]

Google lobbied for two bills that made Nevada the first state where autonomous vehicles can be legally

operated on public roads. The first bill is an amendment to an electric vehicle bill that provides for the licensing

and testing of autonomous vehicles. The second bill will provide an exemption from the ban on distracted

driving to permit occupants to send text messages while sitting behind the wheel. The two bills came to a vote

before the Nevada state legislature’s session ended in June 2011. It has been speculated that Nevada was

selected due to the Las Vegas Auto Show and the Consumer Electronics Show, and the high likelihood that

Google will present the first commercially viable product at either or both of these events. Google executives,

however, refused to state the precise reason they chose Nevada to be the maiden state for the autonomous

car.[6]

Nevada passed a law in June 2011 concerning the operation of autonomous cars in Nevada, [4][5][6] which went

into effect on March 1, 2012.[7] A Toyota Prius modified with Google's experimental driverless technology was

licensed by the Nevada Department of Motor Vehicles (DMV) in May 2012. This was the first license issue in

the United States for a self-driven car.[7] License plates issued in Nevada for autonomous cars will have a red

background and feature an infinity symbol (∞) on the left side because, according to the DMV

Director, "...using the infinity symbol was the best way to represent the 'car of the future'." [11] Nevada's

regulations require a person behind the wheel and one in the passenger’s seat during tests.

Google's robotic test cars have about $150,000 in equipment including a $70,000 LIDAR (laser radar) system.

[20] The range finder mounted on the top is a Velodyne 64-beam laser.[21]

Odometry is the use of data from moving sensors to estimate change in position over time. Odometry is used

by some robots, whether they be legged or wheeled, to estimate (not determine) their position relative to a

starting location. This method is sensitive to errors due to the integration of velocity measurements over time to

give position estimates. Rapid and accurate data collection, equipment calibration, and processing are required

in most cases for odometry to be used effectively.

The word odometry is composed from the Greek words hodos (meaning "travel", "journey")

and metron (meaning "measure").