On October 18, 2002, at 1655 mountain daylight time, a Piper PA-28-180, N33170, registered to and operated by the pilot, was substantially damaged during a forced landing on a highway cloverleaf approximately 1/2-mile short of runway 35 at the Salt Lake City, Utah, International Airport. The private pilot, the sole occupant aboard, was not injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the personal flight being conducted under Title 14 CFR Part 91. The flight originated at Mesquite, Nevada, approximately 1335 Pacific daylight time, and was en route to Bountiful, Utah. The following is based on a telephone conversation with, and the accident report submitted by, the pilot. After servicing the airplane with fuel, he estimated there was 32 to 33 gallons of fuel on board because the fuel level was just below the tabs in the tank, which indicate approximately 17 gallons in each tank. The en route portion of the flight into the Salt Lake City area, at 9,500 feet msl (mean sea level), was uneventful. Approximately 1650, after descending to 6,000 feet msl and obtaining clearance to transit Class B airspace (TCA, or Terminal Control Area), the engine began "running rough." The airplane was then approximately 5 miles southeast of the Salt Lake City International Airport. After efforts to restore full power failed, the pilot declared an emergency and was cleared to land on runway 35 at Salt Lake City International Airport. The engine then lost all power and the propeller began windmilling. After establishing the best glide speed of 80 mph, the pilot was unable to glide to the airport, and he made a forced landing on a cloverleaf on Interstate Highway 80. During the landing the airplane struck a corrugated metal drainage culvert, collapsing the nose and right main landing gear. According to an FAA aviation safety inspector who responded to the scene, approximately 1/3-gallon of fuel was drained from the airplane's fuel system. The salvage company that retrieved the airplane reported draining slightly more than 1 quart of fuel from both fuel tanks and the fuel strainer. No fuel stains were noted on the wings or underneath the fuselage.