Washington, Feb 10 (Reporter) A small airplane has crash-landed on interstate I-75 in Collier County, Florida, and collided with a vehicle, the Florida Department of Highway Safety and Motor Vehicles said. The authorities have closed the southbound portion of the highway, the Florida Department of Highway Safety and Motor Vehicles said in a statement on Friday. The airplane, a Bombardier Challenger 600, was traveling to Florida from Ohio, the statement said. The aircraft experienced engine failure and the pilot was forced to try to land on the highway, the statement added. The number of people on board the airplane remains unclear at present and it is unknown whether there are any casualties and injuries, according to the statement...////...