This aerial photo shows the wreckage of the Asiana Flight 214 airplane after it crashed at the San Francisco International Airport in San Francisco, Saturday, July 6, 2013. (Photo by Marcio Jose Sanchez/AP Photo)

A man, right, throws a chair at a business window as another man tries to restrain a woman attempting to stop the damage, after march to City Hall for Freddie Gray, Saturday, April 25, 2015 in Baltimore. Gray died from spinal injuries about a week after he was arrested and transported in a police van. (Photo by Alex Brandon/AP Photo)

A Colombian air force helicopter retrieves the bodies of victims from the wreckage of a plane that crashed into the Colombian jungle with Brazilian soccer team Chapecoense onboard near Medellin, Colombia, November 29, 2016. The chartered plane was carrying a Brazilian soccer team to the biggest match of its history when it crashed into a Colombian hillside and broke into pieces, killing 75 people and leaving six survivors, Colombian officials said Tuesday. (Photo by Jaime Saldarriaga/Reuters)

A South Korean military vehicle drives past barricades at the military check point, near the Demilitarized zone (DMZ) separating South and North Korea on December 20, 2011 in Paju, South Korea. (Photo by Chung Sung-Jun/Getty Images)

People ride a prototype of a driverless vehicle as it is moves through a pedestrian area in Greenwich, east London, February 11, 2015. Britain has begun testing driverless cars in four cities, launching the first official trials ahead of a series of planned rule reviews to accommodate the new technology. (Photo by Suzanne Plunkett/Reuters)

Automated guided vehicle robot “Ray” lifts up an Audi car during a pilot project at the parking area of the Audi plant in Ingolstadt, Germany, May 13, 2015. The robot has been designed to help make work more efficient and more comfortable for employees, some whom walk up to eight kilometres a day, while coordinating the finished cars for the subsequent train transportation. “Robot Ray” technology, currently being used at Dusseldorf International Airport in Germany, claims to be able to park 60 per cent more vehicles in one area compared with a human driver. (Photo by Michaela Rehle/Reuters)

A motorcycle Majestic 350 CC 1931 is displayed on February 5, 2014 at the Grand Palais in Paris on the eve of an auction of luxury vintage cars. (Photo by Francois Guillot/AFP Photo)

The first prototype of the HIRIKO electric car, during the global launch of Hiriko Driving Mobility, at the EU Commssion headquarters on January 24, 2012 in Brussels, Belgium. (Photo by Geert Vanden Wijngaert/Getty Images)