Mercedes-Benz is testing its autonomous car on Californian roads
Autonomerc mobility MORE THAN MEETS THE EYE: On the outside, the S500 looks like any other S-Class, but inside, it bristles with wires and computers. The car has eight radar sensors - two in front, two behind, and four all-round sensors to detect objects and obstacles.rnPH

WILL a cactus falling in the desert make a sound if there's no one to hear it? Does an autonomous car need a steering wheel if nobody is driving it?

The second may not actually be a philosophical question but Mercedes-Benz has an emphatic answer nonetheless.

According to the German luxury carmaker, the steering wheel, throttle and brake pedals will remain standard equipment because it "does not want to automate the fun out of driving".

Mercedes-Benz is currently one of those at the forefront of autonomous mobility. Its fully driverless S-Class navigates through urban traffic while you sit back and literally relax. Last year, a Mercedes-Benz S500 Intelligent Drive model equipped with near-production-standard technology drove autonomously for 100 km between the German cities of Mannheim and Pforzheim.

This year, the brand with the three-pointed star received a licence from the US authorities allowing it to test vehicles in autonomous driving mode in daily traffic on Californian roads. The activities are conducted out of Mercedes-Benz's research facility in Silicon Valley, where it has had a presence for nearly 20 years.

On a recent visit to Mercedes-Benz Research and Development North America (MBRDNA), there was an opportunity to ride in the S500 Intelligent Drive.

On the outside, the S500 looks like any other S-Class. But inside, it bristles with wires and computers. The car has eight radar sensors - two in front, two behind, and four all-round sensors to detect objects and obstacles. Radar sensors are different from ultrasonic sensors, which are used for parking and which the car also has.

There are also three cameras - two in front and one behind. One of the front cameras recognises lane markings based on the car's own digital map, while the other detects obstacles up to 200 metres ahead. The rear unit, meanwhile, is for localisation purposes; it can recognise buildings for more accurate positioning of the car. Because the cameras collect tonnes of data, such as facial features and vehicle ID details, the system anonymises it by turning what it sees into shapeless blobs that are colour-coded according to their proximity. Red objects are the closest, blue is farther away and green is deemed a safe distance.

For security purposes, the car's computer is closed off to outside links.

Despite the high-tech safety nets, sitting in a moving S500 Intelligent Drive can initially be unnerving. It cruises at a very brisk 40-45 mph (64-72 kmh) along the wide avenues of Sunnyvale, California, almost zipping through four-way junctions. The ride is extremely smooth though, with each lane change and corner taken comfortably and confidently. It will even slow down to enter the highway and merge with faster traffic before accelerating to the maximum 65 mph (105 kmh) limit.

But that speed is not its highest. According to Mercedes-Benz, maximum speed depends on the type of sensor used. The farther a sensor's range, the faster the car can go safely. The Merc's sensors see up to 200 metres, while those on the Google self-driving car are said to be good for only 100 metres. It is possible to get better sensors and hence, go faster. But there is a price to pay - they also cost and weigh more.

But perhaps even more interesting is how MBRDNA believes autonomous driving could revolutionise a car's interior. To envisage if it will become a relaxing lounge or mobile office, it has created a virtual 360-degree experience of an autonomous luxury saloon with variable seating.

Four rotating lounge chairs allow for a face-to-face seat configuration when the front passengers turn around to face those behind. If they prefer to do the driving themselves, there is an extendable steering wheel.

There is a continuous exchange of information between vehicle, passengers and the outside world. With the interior becoming a digital living space, the passengers can interact intuitively with the vehicle by means of gestures or touch displays.

The vehicle's surroundings, including pedestrians, other road users or buildings, are also brought inside the car and portrayed as fluid all-round information on displays.

Even more intriguing is that the Merc research facility has a resident futurologist, who, among other things, studies the role of humans in future mobility. One thing is for sure though; they should still have fun driving a Mercedes.