PLT IN SMA IN IMC CRUISE HAD ENG FAILURE. FORCED LNDG ON HIGHWAY.

Narrative

I TOOK OFF TO THE S AND OBTAINED AN IFR CLRNC FROM LAS VEGAS APCH TO MONTGOMERY FIELD. CLB WAS UNEVENTFUL; AND AT MY CRUISING ALT OF 10000 FT I LEVELED OFF; FULL THROTTLE; IN IMC CONDITIONS IN V538. I WAS CRUISING FOR APPROX 10 TO 15 MINS WHEN I NOTICED A SUDDEN DROP IN CABIN TEMP. I SCANNED ALL THE INSTS AT THIS POINT; AND ALL APPEARED TO BE FUNCTIONING NORMALLY. THE OAT WAS INDICATED AT -15 C. I LOOKED AT THE WINDS AND WINDSHIELD FOR ICE; BUT NONE WAS EVIDENT. ABOUT 30 SECONDS LATER THE END INDICATED A SLIGHT ROUGHNESS; AND 15 SECONDS AFTER THAT THE ENG QUIT COMPLETELY. MY POSITION ON V538 WAS OVER THE MCCULLOUGH MOUNTAIN RANGE. I IMMEDIATELY APPLIED CARB HEAT; SWITCHED ON FUEL BOOST PUMP AND CHANGED FUEL TANKS. FUEL PRESSURE WAS NORMAL. THE ENG WOULD NOT RESTART; SO I STARTED TO DSND. DURING DSCNT I WAS CONTINUOUSLY THROTTLING THE ENG TO TRY TO GET SOME PWR; BUT IT CONTINUED TO WINDMILL ALL THE WAY DOWN. I KEPT CARB HEAT ON AND THROTTLE IN FOR THE LAST 1000 FT UNTIL FINAL APCH; HOPING FOR A RESPONSE; UNTIL I FINALLY PULLED THE THROTTLE AND LANDED ON THE ROAD. THE ONLY DAMAGE TO THE ACFT WAS INCURRED ON ROLLOUT WHEN MI MARKERS ON EITHER SIDE OF THE ROAD IMPACTED THE WINGS. (IT WAS ONLY A 15-20 FT WIDE ROAD). NO INJURIES OF ANY TYPE WERE SUSTAINED BY MYSELF OR MY PAX. NO VEHICLE WAS ON THE ROAD AT THE TIME. AT NO TIME THROUGH THE ENTIRE FLT WAS ICE EVIDENT ON ANY PART OF THE AIRPLANE. 15 MINS AFTER LNDG I RESTARTED THE ENG WITH LITTLE EFFORT; AND PULLED 2000 RPM. THE ENG HAD NOT LOST ANY OIL DURING THE FLT. ALL ACFT SYSTEMS WERE OPERATIONAL. THE PROBLEM WAS CLRLY CARB ICING.