This is a Citroen DS, after going through heavy modifications to be able to test tires. It is made by Michelin in 1972 and weighs more than ten metric tons. PLR comes from Poids Lourd Rapide or Fast Semi Truck. Inside this vehicle there is enough space for a mid-mounted tire-testing machine along with the crew. This is quite a freaky car (or whatever it is) which holds two small-block Chevy V-8 engines (350 cubic inches), one to power the rear six wheels and another to spin the tire testing machine mentioned above. PLR is steered by all four front wheels and can reach nearly 180 km/h. It absolutely deserves its nickname - “mille-pates”, or millipede.
PLR is made with the purpose to test truck tires at high speeds without the risks of using trucks. If a tire blows they don’t have to worry about losing control of the vehicle. The ten wheels and hubs come from an HY van, also produced by Citroen. At this time Citroen is owned by Michelin and that is why they use Citroen models to create this tire tester.
For comparison, the “simple” Citroen DS uses flat six cylinder engine with air cooling and volumetric displacement of 1911 cubic centimeters. The DS had the gearbox mounted in front of the engine with the differential in between, so that DS is considered to be a mid-engine front-wheel drive car.
Source : http://www.interestingengineering.com