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In a famous episode of UK sitcom Only Fools and Horses, the protagonists chase an ambulance through London after a deal goes awry – and then lose it as it goes straight through a red traffic light. “How could you possibly lose an ambulance?” exhorts Del Boy. “It’s a ruddy great big white thing with a flashing blue light on the top! And in case your peepers ain’t too clever, it makes a sound like an air raid siren!”

This scene came to mind - albeit with the days of white ambulances in the UK all but gone - following Google’s latest patent offering in the connected car space; this time, sensing the presence of emergency vehicles and directing the car appropriately to yield to them.

The filing, which was first spotted by the people at PatentYogi, describes a system and method for ‘detecting and responding to emergency vehicles’.

Google hopes for the system to work through analysing a flash pattern of two or more light sources, filtering out those which do not match its records, such as light sources which have colours not related to emergency vehicles, or light sources not in line with other geographical data, and acting accordingly.

“An important component of an autonomous vehicle is the perception system, which allows the vehicle to perceive and interpret its surroundings using cameras, radar, sensors, and other similar devices,” the patent notes. “An approaching emergency vehicle, such as a police car, having engaged its flashing lights may need to be given priority and right of way on the road. Thus, an autonomous vehicle may need to accurately detect and properly respond to approaching emergency vehicles.”

This is the latest example of driverless cars being trained to obey the rules of the road – even the more obscure ones. Under the Highway Code section 4.31 – ‘situations needing extra care’ – the instruction is clear: “If an ambulance, fire engine, police or other emergency vehicle approaches using flashing blue lights, headlights and/or sirens, keep off the road.” As another example Google, as well as Volvo, have made strides in enabling cars to better understand cyclists’ hand signals.

The patent was filed in August 2014, and published earlier this month.