The Mercedes-Benz global autonomous test drive runs into some singular challenges in Australia.

Turning to the right from the left-hand lane is one; flashing speed-limit traffic signs are another. Then there’s the problem of kangaroos hopping in and near roadways.

All are special challenges in the third leg of the Mercedes-Benz Intelligent World Drive, a 5-month-long test of autonomous-driving functions on all five continents using a vehicle based on the German automaker’s S-Class.

In Australia, the test vehicle is facing unique conditions and situations with automated test drives on highways, motorways and in the city of Melbourne.

A Mercedes-Benz spokesman tells WardsAuto in an email the S-Class did not encounter kangaroos – not live ones, anyway.

“During the drive from Sydney to Melbourne we did regularly pass roadkill throughout the drive, which was noted by our engineers,” he says.

The global drive started in September at the Frankfurt auto show as a way to adapt more highly automated driving functions to national traffic and user practices. The aim is to gather global insights into real-life traffic conditions.

The test vehicle is collecting comprehensive information in a variety of complex traffic situations and in doing so is sounding out the limitations of the current systems.

The focus of the test drives in Australia, taking place from Sydney via Canberra and Albury to Melbourne and its urban traffic, is on detecting traffic signs specific to the country and testing out the Aussies’ innovative digital light system.

Instead of the standard speed-limit signs made of metal, Australia’s traffic system is increasingly using electronic displays with variable speed limits designed to improve both traffic flow and safety. They are fitted with a bright white LED display, a red LED ring and a yellow LED warning lamp and can display not only speed limits but also simple symbols and letters.

Some are positioned one after another, to ensure dynamic traffic flow, and can change what they display within fractions of a second.

The signs present a key challenge to the performance of the test car’s digital camera and the quality of its digital mapping data, which allow automated driving functions such as active speed-limit assist and active distance assist to function reliably.

A further peculiarity is the traffic situation referred to as a “hook turn,” which is to be found only in Melbourne.

It controls turning off from roads also used by trams. Drivers wanting to turn off to the right across the tram lines must get into the left-hand lane. The sensor system of an automated and autonomous vehicle must be able to detect the hook-turn sign and interpret it correctly.

Then there’s the wildlife. Compared with European or American road traffic, Australia has an extremely high number of animals crossing the road, particularly in sparsely populated areas.

Just as high is the number of accidents involving emus, koalas, wombats and kangaroos.

Kangaroos represent a particular challenge for a sensor system, as they do not run across the road but hop. They reach a height of 5 ft. (1.5 m) and a speed of 37 mph (60 km/h). There also is the question of how the vehicle should react when it detects animals.

After Australia, the test drives move to South Africa, where pedestrian detection in many unfamiliar situations will play a significant role.

Test drives in Greater Los Angeles and Las Vegas will concentrate on evaluating the car’s driving behavior in heavy U.S. urban traffic as well as when traffic is overtaking on the right on highways.

 The final stop of the Intelligent World Drive will be the Consumer Electronics Show in Las Vegas in January.

In the past seven years, Mercedes-Benz has conducted about 5,100 test drives around the world with 175 test vehicles for validations of driver-assistance systems in the field. The performance of the systems was assessed over 5.9 million miles (9.5 million km) in Europe, the U.S., China, Australia and South Africa.