In 1939 Dr Thomas C. Poulter, Director of the Armour Institute, Chicago and a veteran of Byrd's second Antarctic expedition, designed and constructed a 30 tonne wheeled vehicle known as the Snow Cruiser for use with the US Antarctic Service Expedition. Designed for self-contained long-distance travel, the vehicle had many new features including twin diesel engines, independent electric drive and steering on each of its four wheels, and a light aircraft carried on the roof. It was built in Chicago and tested briefly on sand dunes nearby, before being driven to Boston amid much public interest for shipment to Antarctica. At the Bay of Whales the vehicle quickly became bogged down in snow, and never moved farther south than the expedition's winter quarters. Modern evaluation of wheel-snow interaction suggests that the Snow'Cruiser unladen was three to five times too heavy for its tyres to support it on snow surfaces. It was nevertheless a bold attempt to push forward the frontiers of mobility in exploration, which failed in a spectacular fashion. The vehicle was left behind when the expedition returned home, and has subsequently been lost.