The rx450H is downright dangerous. The 4 wheel drive does not switch "on demand" as the advertising says. I live in snowy Massachusetts and do not need permanent 4 wheel drive, but it is essential when the roads are full of snow or ice. I was puzzled at first that the 4 wheel drive only actuated under 25 mph. I tested it on sharp corners in the snow: The back slid out; and on faster, gradual corners: The car side slipped. Never did the 4 wheel drive switch on and correct the slide. I looked in the manual for the method to manually activate 4 wheel drive but couldn't find it. I contacted Lexus. They said that I should use the snow switch. This is a menu item which annoyingly must be switched on every time you drive. It didn't work as it only changes the gear and acceleration characteristics like any other winter/summer switch. They also said that it should work at high speeds when more power is needed. I tried that and found that at 60 mph if I absolutely floored the accelerator on a steep hill the 4 wheel drive would switch on briefly. That's hybrid technology being used to reduce consumption"! I went back to my dealer: What was I doing wrong" after two months of phone tag with the dealer and Lexus, the dealer promised to pick up the car and test it. After a week of telephone calls they said there was no point in testing the car as it was working "as designed". however it wasn't working as advertised which is that the 4 wheel drive will come on "as needed". I'd say that a broad skid in snow is "as needed". Lexus does not intend to do anything about this complaint. They put me onto a "business development" specialist who tried to upsell me on a non-hybrid 4X4 which he said had "a non slip differential" and would therefore have better handling. I consider it very dangerous that a driver thinks they will have control because of Lexus advertising and salesman claims but will likely loose control in snow or ice and cause a serious accident.

- Concord, MA, USA