Cessna 150 pilot reported landing safely on a public road following an engine failure that was later traced to fuel exhaustion.

Narrative

The purpose of this specific flight was to meet the night cross-country requirement of 100 NM and 2 hours; as well as the 10 takeoffs and landings at a towered airport.We took off with approximately 25 gallons of fuel; which was sufficient according to our pre-flight cross-country planning and within the aircraft's weight and balance limits.Each of us conducted an independent pre-flight inspection in accordance with the POH.Fuel levels were verified using a dipstick in addition to the aircraft's fuel gauges.I was the PIC. We departed from ZZZ and conducted the 10 required takeoffs and landings at ZZZ1. After completing that portion; we continued our flight to ZZZ2. We landed there to complete the 100 NM cross-country requirement; then proceeded to ZZZ3 to refuel; use the restroom; and wait for sunrise to begin practicing commercial maneuvers and checkride preparation.While descending into ZZZ3; I was acting as PIC. We were flying in an area with wind turbines and power cable hazards.During the descent; we experienced an engine failure. I identified the issue and began searching for a suitable landing site while executing the appropriate emergency checklist.A nearby highway was within gliding distance. To avoid the hazards of wind turbines and power lines; we agreed to land on the highway.After checking for traffic and consulting the sectional chart available on our EFB; we identified a clear spot with no traffic at that moment.We executed a safe landing at the proper airspeed; touching down on the centerline of the highway.We followed proper evacuation procedures and pushed the aircraft off the highway to eliminate any hazard to oncoming traffic; using handheld light signals to ensure safety.Authorities were contacted to ensure the continued safety of highway traffic.After sunrise; we conducted another thorough pre-flight inspection to determine the probable cause of the engine failure. We concluded that it was likely due to fuel starvation; as both fuel tanks were found to be empty.Our pre-flight calculations and fuel gauges had confirmed we had sufficient fuel to remain legal under night VFR. To investigate further; we inspected the aircraft for fuel leaks; none were found.After refueling the aircraft; we conducted an engine run-up; all engine parameters were within operational safe limits.With the assistance of local authorities; we temporarily blocked highway traffic and inspected the area for obstacles in the intended takeoff path. Local law enforcement agreed to help block traffic on both sides of the highway to allow for a safe takeoff run.