One of the major design considerations when the first LS 400 was being prototyped was reducing its drag co-efficent (Cd), or the amount of wind turbulence the car experienced when in motion. A low drag helps with fuel efficiency and reduces the amount of energy needed to keep the car moving, and when the car was introduced, the LS 400 proposed to have lowest Cd of any standard passenger car.
So when Autospeed decided to publish a series of articles examining the aerodynamics of various vehicles, including a 1991 Lexus LS 400 seemed elementary. They also took to an interesting method of investigation: tufts of wool were taped over the entire car, which was then driven down an empty highway at 80mph, all while these tufts were examined for turbulence. Quite a bit cheaper than renting a windtunnel!
This was by no means an exact experiment, but the results are interesting nonetheless. They discovered a bit of air turbulence around the bottom of the rear window, though minimized by the design of the C pillars, and some additional unsteady air flow around the front wheel wells.
At the very least, this was quite an entertaining visualization technique of a key component in vehicle design.