Power Loss and Restart Attempt
While en route at night at approximately 18,000 feet above mean sea level (MSL), the aircraft's engine lost power. The pilot was unable to restart the engine. During the restart attempt, the pilot observed that the carburetor heat control would not move fully to either the on or off position.
Navigation and Runway Lighting
The pilot requested radar vectors to the nearest airport. However, from about 7.5 miles away, the pilot could not see the airport. The pilot was unaware that the runway lights were activated by keying the microphone button five times on frequency 122.8 MHz. From approximately 17,000 feet MSL, the pilot was able to see a highway and the lights of vehicles on it.
Landing and Impact
The pilot elected to land on the highway. During the landing in heavy rain, the left wing and engine struck trees adjacent to the roadway.
Post-Accident Examination
An examination of the engine revealed no evidence of any pre-impact malfunction or failure.