A Google patent has revealed that the firm’s self-driving cars will be able to detect and respond to a cyclists’ hand signals.

The documents reveals that the car’s array of sensors will notice a cyclist among other objects and vehicles on the road.

It can then watch their arms and hands for gestures indicating that they are about to turn or slow down, and change its own speed in response.

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A Google patent has revealed that the firm’s self-driving cars will be able to detect and respond to a cyclists’ hand signals. Its computers compare the distance between the cyclist’s hand and head to decide whether a cyclist is turning or stopping, the patent says

Google announced its self-driving cars would be capable of doing this last year, but the latest patent reveals new details about how it would work.

It describes how the car would use a combination of a camera, Lidar and radar to collect information about objects that surround the car.

It does this by examining the height of objects it may think are cyclists compared with the average height of cyclists it has previously identified.

The car measures the distance between the top of the cyclist’s head and the pavement at various ranges, as well as noting its position on the road.

Pictured is a patent drawing of how Google expects its system to know when a cyclist is turning right. The car measures the distance between the top of the cyclist’s head and the pavement at various ranges, as well as noting its position on the road

The documents reveals that the car’s array of sensors will notice a cyclist among other objects and vehicles

Google’s algorithms can then decide whether a cyclist is present, and then identify parts of his or her body.

Its computers compare the distance between the cyclist’s hand and head to decide whether a cyclist is turning or stopping, the patent says.

The algorithm will also look at the angle at which the cyclist’s elbow is bending, and the size and shape of the cyclist’s hands, arms and head.

‘The computing device may be configured to determine other subsets relating to other aspects of the cyclist, such as one or more subsets indicative of a type of vehicle of the cyclist,’ the patent reads.

HOW DOES GOOGLE'S AUTONOMOUS CAR WORK? Google's prototype two-seater 'bubble' cars have buttons to begin and end the drive, but no other controls. An on-board computer uses data from sensors, including radar, a laser and cameras, to make turns and negotiate its way around pedestrians and other vehicles. Under the vision unveiled by Google, passengers might set their destination by typing it into a map or using commands. The cars are also expected to be electric, capable of going 100 miles (160 km) before needing to be recharging. The front of the vehicle has a soft foam-like material where a traditional bumper would be and a more flexible windscreen, in an attempt to be safer for pedestrians. The prototypes are restricted to speeds of 25mph (40 km/h) and the ability to self-drive will depend on specifically designed Google road maps tested on the company's current fleet of vehicles. But ultimately the vehicles will be faster and will be able to use Google's extended maps service, using GPS technology to locate the vehicle's exact position on an electronic map. A combination of radar, lasers and cameras sitting on top of the roof give the car a 360-degree 'view', with sensors linked to computer software able to 'see' and identify people, cars, road signs and markings and traffic lights. Advertisement

‘In some embodiments, the type of vehicle of the cyclist may include other means of transportation such as a scooter or moped.’

The Washington Post notes that the patent remains vague, leaving open different possibilities for exactly how Google’s self-driving cars could work.

Google says it begun discussions with most of the world's top automakers in a bid to get self-driving cars on the road by 2020.

In March, a separate patent revealed that Google's self driving car could have airbags both inside and out.

The algorithm will look at the angle at which the cyclist’s elbow is bending, and the size and shape of the cyclist’s hands, arms and head

It shows an external airbag system in action that inflates if the car hits a pedestrian or other object.

The airbags would be made a new 'memory foam' material that doesn't simply cause the pedestrian or cyclists to bounce off.

The head of self-driving cars for Google expects real people to be using them on public roads in two to five years.

Chris Urmson says the cars would still be test vehicles, and Google would collect data on how they interact with other vehicles and pedestrians.

Google is working on sensors to detect road signs and other vehicles, and software that analyzes all the data.

Google's patent shows an external airbag system to protect pedestrians and cars in the event of a crash

The small, bulbous cars without steering wheels or pedals are being tested at a Google facility in California.

Urmson wouldn't give a date for putting driverless cars on roads en masse, saying that the system has to be safe enough to work properly.

He told reporters at the Automotive News World Congress in Detroit that Google doesn't know yet how it will make money on the cars.

Urmson wants to reach the point where his test team no longer has to pilot the cars.

'What we really need is to get to the point where we're learning about how people interact with it, how they are using it, and how can we best bring that to market as a product that people care for,' he said.

Google may face state regulatory hurdles depending on where it chooses to test the cars in public. Under legislation that Google persuaded California lawmakers to pass in 2012, self-driving cars must have a steering wheel and pedals.

Several other states have passed laws formally allowing autonomous cars on public roads without that restriction.

The company in December announced that it had a fully functioning prototype that's been driving on its test track.