Experts think it's just a matter of time before self-driving vehicles appear on our roads. Would you be happy if a computer was in charge of your car?
We are only a few years away from a time when many, if not most, of the cars on our streets drive themselves.
That is according to the technology firm Google, which has this month in California been demonstrating its new driverless cars to journalists from all over the world.
Less congestion, more free time
Driverless cars use on-board computers and Wi-Fi or mobile phone communications to assess road conditions and react to other vehicles, pedestrians and traffic signals.
The people behind this technology say that self-driving cars have a number of advantages.
Firstly, the computer sensors can react more quickly than humans, which should reduce the number of collisions.
Secondly, driverless cars will be able to communicate with each other to regulate traffic speeds and thus cut congestion and fuel emissions.
And finally, the vehicles free their owners from having to concentrate on the road so they can make better use of their travelling time.
2017 launch date
Google has set a date of 2017 for bringing the cars to market, and many manufacturers are already well along the road to developing these new vehicles.
In Gothenberg, Sweden, Volvo has just launched a pilot scheme involving five prototypes on a limited number of the city's streets.
Here in the UK, the government recently announced plans to make Britain a global centre for self-driving cars.
Ministers are currently carrying out a study to find out what legal and regulatory changes would be necessary to make this country the best place to develop and test the vehicles.
Obstacles to driverless cars becoming a reality
So what is standing in the way of driverless vehicles becoming an everyday reality?
The first step is to make a car which can drive itself safely in a wide range of situations with no input from its human occupants.
Jim Holder, editor of What Car?, believes this is already possible.
"We are already experiencing cars that can do what were jobs of the driver - dipping lights, self-parking and so on," he says.
"The next step involves the car doing tasks in very specific circumstances, such as negotiating traffic-clogged streets at low speeds with the driver's hands on the wheel.
"The third stage is a full driverless car, where all occupants might be in the back, for instance.
"The likes of Nissan, Volvo, Mercedes, BMW, Google, and Tesla are well advanced with the technology: these cars could be on the road today, but the regulatory hurdles remain huge."
Regulation and insurance
These legal issues are perhaps the biggest obstacle. In the UK and the EU, traffic laws are based on the 46-year-old Vienna Convention, which requires the driver to be in control of their vehicle at all times.
The government is calling for a new international legal framework to cover self-driving cars, in particular who is to blame in the event of an accident.
At the same time, car insurance providers face a significant challenge in working out how motor cover will be applied to this new breed of vehicles.
Popular opinion is another potential stumbling block.
A recent AA poll found that most people said they wouldn't trust assurances from manufacturers or the government than driverless cars were safe.
And two-thirds said they enjoyed driving too much to be interested in a self-driving vehicle.
Simon Williams at the RAC says: "We suspect it will be difficult for people to come to terms with giving up control of their vehicle to a computer.
"Many vehicles already have features such as automatic braking and it is claimed that driverless technology is able to identify hazards more effectively than a person can.
"But many motorists will be concerned about not being able to control the speed of their vehicle for the conditions or layout of the road in front of them."
Government officials, however, believe that a programme of public demonstrations and test drives could help sway opinion.
Driverless car 'will happen'
What Car? editor Jim Holder adds: "In all likelihood, we expect to see drawn-out pilot schemes initially."
He adds that this will take place "most likely in progressive new cities, with simple road layouts, the right infrastructure and new populations who buy in to the trials".
"Thereafter, it will be a long, slow build-up to the globalisation of the technology.
"But it will come. It brings with it the promise of accident-free mass transport and, in the long term, that is too powerful a message for the rule-makers to stand against."
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