C172 FORCED LNDG ON A FREEWAY DUE TO FUEL EXHAUSTION.

Narrative

UPON PREFLTING THE AIRPLANE I SAW AND FELT THE FUEL TANKS WERE FULL. I WAS PLANNING ON A 3 HR FLT OF TFC OBSERVATION. I DID A NORMAL RUN-UP CHK. DURING THAT CHK; I SAW THAT THE FUEL TANK INDICATORS WERE INDICATING FULL TANKS ON BOTH SIDES. I CHKED THAT THE FUEL FEED SELECTOR WAS ON BOTH TANKS DURING THE RUN-UP CHK. I DO NOT EVER RELY ON THE FUEL INDICATORS; BUT DURING MY PREFLT; I VERIFIED THAT I HAD FULL FUEL; WHICH WOULD BE ABOUT 5 HRS OF FUEL. ABOUT 1.5 HRS INTO THE FLT; I NOTICED AN UNEVEN BURN. I LEFT THE FUEL SELECTOR ON BOTH. THE R TANK WAS HALF FULL AND THE L TANK WAS 3/4 FULL. 2.3 HRS INTO THE FLT; I NOTICED THAT THE R TANK WAS ALMOST EMPTY AND THE L TANK WAS LESS THAN 1/2 FULL. I DID NOT TRUST THESE GAUGES AND HAVE NOT TRUSTED THEM IN THE PAST. SINCE I WAS SHOWING I HAD FUEL; I CONTINUED THE FLT. I CONTINUED ALSO DUE TO KNOWING I TOOK OFF WITH FULL FUEL. AT EXACTLY 3.0 HRS IN THE FLT; I WAS STILL SHOWING FUEL IN THE L TANK AND NONE IN THE R TANK. AT THIS TIME; THERE WERE 8 MINS LEFT IN THE FLT AND I WAS WITHIN 5 NM OF THE ARPT. WHEN CALLING THE TWR TO ENTER THE AIRSPACE; THE ENG BEGAN TO SPUTTER. I IMMEDIATELY PUT THE FUEL TO L TANK AND MIXTURE RICH. THIS GOT THE PLANE GOING AGAIN; BUT ONLY FOR ABOUT 30 SECONDS. AFTER THAT; THE PROP JUST WINDMILLED AND I HAD A PLACE TO LAND; BUT IT WAS OCCUPIED BY CHILDREN. I WAS FORCED TO LAND ON THE FREEWAY. THERE WAS NO INJURY OR DAMAGE. I THOUGHT I HAD FUEL BUT INSPECTION OF THE TANKS REVEALED NO FUEL IN R TANK AND MARGINAL FUEL IN L TANK.