Prepare for the invasion of the road-bots; Driverless cars
are now clever enough to cruise intraffic and could
slash the incidence of road accidents. But until legal
and psychological issues are sorted out, the military
might be the only ones to benefit
Michael Reilly, Victorville, California
DIESEL engine idling, Alice peers left, right, then straight at
me. With her headlights on in the hazy morning, the imposing grey
Ford van emits a loud beep, warning the world she is about to set
off with no one at the wheel.
We're at the starting line of this year's DARPA Urban Challenge
(UC), a 6-hour, 100-kilometre race along the roads of a simulated
city organised by the Pentagon's Defense Advanced Research
Projects Agency (DARPA). Alice's laser eye swings cautiously
around. A robot can't be nervous, but its human creators, a team
of researchers from the California Institute of Technology in
Pasadena, certainly are. They hope to prove that cars like Alice
are a glimpse of the future.
It's 26 October, the first day of the race's qualifying round, a
week-long test of robot road skills. Those that pass will take
part in the race, in which they must navigate roads autonomously,
obey the laws of traffic and, hardest of all, avoid each other.
The winning team gets $2 million and a spot in robotics history.
The US government hopes to turn the winners into military supply
vehicles for war zones, while some companies hope to make robotic
cars a feature of our cities, and maybe reduce road deaths into
the bargain.
As it turns out, Alice won't be the one to take us into this brave
new world. A later test reveals that beneath her cautious
exterior lies an affinity for accelerating into oncoming traffic.
She does not advance to the finals.
Nonetheless, her brethren do the robot world proud. Of the 11
teams that race in the final on 3 November, six cross the finish
line. It's a gruelling race through unpredictable moving traffic,
parking lots, construction sites and even an excursion down a
dirt road into southern California's high desert. Despite a
couple of fender benders, the results are encouraging. Driverless
cars on our highways might be closer than you think.
The UC isn't the Pentagon's first foray into robot racing. In the
Grand Challenge (GC) of 2004 and 2005, robot cars had to navigate
a dirt course across the Mojave desert (New Scientist , 19
November 2005, p 48). That race, in which robots had to avoid
stationary obstacles and follow a list of GPS coordinates known
as waypoints, was simple by comparison, though. According to
veteran robot racer William Whittaker, whose Carnegie Mellon
University team built the UC's winning car, Boss, it consisted of
nothing more than "barbaric, flat-out charges with big rooster
tails of dust". The UC, on the other hand, introduces much more
sophisticated challenges.
As the vehicles race together around the track, they must detect
and avoid moving objects. If another vehicle stops, the robot
cars must work out why and then decide whether to change route,
drive around it or simply wait for it to move again. They must
also obey the rules of the road, such as who has right of way at
a four-way stop sign, and demonstrate skills such as parallel
parking.
Although Boss - a burly Chevrolet Tahoe - was the winner, most of
the UC finalists have the same basic make-up. An array of lasers,
radar emitters, sensors and stereo cameras function as the
robot's eyes. This visual data is fed into software which sews it
together to create a 3D model of the car's surroundings that is
constantly updated.
On the starting line, the cars are loaded with a map of the area
and a list of waypoints they have to pass to ensure they cover
challenging parts of the course. To decide on the best route, the
vehicles start by combining the starting position, the waypoints
and the map, and then modify this plan in response to the
surroundings.
For example, if a car encounters a large object in the road, it
assumes it is a stopped vehicle. The car stops and checks how
close this vehicle is to a traffic light, stop sign or
intersection, which might indicate a reason for the delay. If the
car doesn't move for a while or is not near an intersection, the
robot determines that it has broken down or is parked, and
overtakes. To do this, it simulates several possible routes,
checks to see if any require breaking the rules of the road -
such as jumping a curb - and then picks the shortest allowable
route.
The real test of the robots' mettle came in "zones" on the course
that were blanked out on the map. When cars enter these, not only
must they navigate using sensors alone, they are usually
instructed to carry out a mission like "park safely in a spot".
Parking is one thing that robots find easier than we do. One of
the zones resembled a shopping mall-style parking lot. Most
people would have driven straight into a spot and then backed in
and out to straighten up, but Boss chose a manoeuvre that hit the
spot straight on by performing a neat pirouette first. Although
this trick is faster, people don't often use it.
In the end money and experience won the day. Boss cruised over the
course at an average of 22 kilometres per hour, narrowly beating
a team from Stanford University in California, which won the GC
in 2005. Both teams spent more than $1 million.
Before driverless cars start driving alongside ordinary traffic,
some challenges remain. Cars have to learn to tell the difference
between a car and other moving objects, such as people. Although
there are no formal plans for another DARPA race, roboticists are
speculating that this ability will be the next skill that DARPA
tests. The UC also didn't test speeds that would be required on a
real highway.
Once the technology is ready, the US army will be first to take
advantage of it. Within a few years, it says, one-third of ground
vehicles could go driverless. The move should save troops' lives
by automating logistics operations. "Twenty per cent of our
transport capacity in Iraq is taken up shipping water to the
troops," says Chuck Jacobus, who led team Cybernet of the
University of Michigan at Ann Arbor. "That's a niche that could
be all robotic and remove a lot of people from exposure to bombs."
Driverless cars won't be reaching our streets any time soon,
however. One of the main reasons is that people might find
accidents caused by driverless vehicles particularly
unacceptable. That means robotic navigation skills and obstacle
avoidance will have to be as near to perfect as possible before
we see any driving around. "The first person that gets killed by
an autonomous vehicle is going to set the field back 18 months,"
says William Kehaly, team leader of Axion Racing. Apart from
anything else, who would be liable in such an accident?
Robot cars will also demand changes to infrastructure. If they
drive without someone in the back seat and need to stop for fuel,
people will need to know how to respond to them. It will also be
a long, and maybe unwinnable, battle to persuade people to give
up their love affair with driving.
Still, the biggest argument in favour of robots seizing the wheel
is safety. Automobile accidents killed 43,000 people in the US
last year, while the World Health Organization reported that road
traffic collisions killed 1.2 million people worldwide in 2002.
By 2030, the WHO projects they will be the 8th leading cause of
death. "We just accept this as reality, and that's really sad,"
says Jesse Levinson of the Stanford team.
That robots would make better drivers is something some
roboticists clearly believe. Distracted by chatting, using
cellphones or eating, human drivers are erratic, whereas a
robot's attention never wavers from the wheel. "Boss has been a
better driver than me for a while," says Whittaker, beaming like
a proud father. Would he trust it to drive him on the highway?
"Sure. Absolutely."
But they can only dramatically lower the gruesome statistics if
they replace today's cars entirely. A few robots on the road
wouldn't make much difference. Roboticists are sure this is the
future. Kehaly thinks the next generation might even view today's
cars as dinosaurs: "Our kids are going to say, 'Remember when we
had to drive our own cars around? That was so weird.'"Handing
over control Michael Reilly
The air-con is on in my Saab Sedan but I'm sweating like a pig. An
Opel Saloon is about to attempt to crash into me.
A game of chicken? Not quite. I'm testing Saab's prototype
car-to-car (C2C) radio communications system, designed to prevent
collisions. Cars communicate with each other and apply the brakes
when necessary.
While DARPA dreams of driverless cars, partial control via C2C
might be closer to reality. The US Federal Communications
Commission has already allocated radio spectrum for cars, and
Japan and Europe have plans to do the same.
As well as preventing crashes between cars, it might also
safeguard pedestrians, provided they could carry transponders
too. Emergency services could also use the technology to signal
their imminent arrival.
Meanwhile technology is already chipping away at driver autonomy.
Several high-end vehicles come with electronic stability control
(ESC), which keeps a car from skidding or rolling over by
controlling the brakes on each wheel independently and using
sensors to determine how the car's chassis is tilting. The US
government now requires that ESC be installed on at least 50 per
cent of cars made in 2009 and on all cars by 2011. "ESC could
save up to 10,000 lives a year [in the US]," says Philip Hedley
of Continental Automotive Systems in Auburn Hills, Michigan.
Also trickling down from the high end is adaptive cruise control,
in which front-mounted radar systems monitor the area ahead.
Another feature showing up on some Lexus, Cadillac, Volvo and BMW
models is a lane departure warning. Most sound an alarm combined
with a warning light, but some simply apply the brakes.
These safety features can also be a distraction, however (New
Scientist , 20 October 2006, p 30). So Hedley says the future is
to integrate them and do more behind the scenes. The first
attempt at such a system, called Presafe, is available on
Mercedes S and E-class cars. When the car's radar system senses a
front-end collision is imminent, it tightens the seat belts,
rolls up the windows and adjusts the seats to maximise the
effectiveness of airbags.
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