On July 31, 1999, at 1102 mountain daylight time, a Mooney M20F, N9390V, registered to and operated by the pilot, was substantially damaged during takeoff near Montrose, Colorado. The private pilot, the sole occupant aboard, sustained a serious injury. Visual meteorological conditions prevailed at the time, and no flight plan had been filed for the flight being operated under Title 14 CFR Part 91. The flight was originating when the accident occurred and the intended destination was Durango, Colorado. According to the pilot's accident report, the airplane had just received an annual inspection in Evanston, Wyoming. On July 26, he took off from Evanston to return the airplane to its home base in Durango, Colorado. While en route, an abnormally high temperature was registered on the cylinder head temperature gauge, and the engine began to run rough. The pilot made a precautionary landing on Colorado Highway 141. The airplane struck several T-posts, denting the leading edge and tearing the bottom of the left wing in two places. A mechanic from Montrose Regional Airport was summoned and temporary repairs were made. A permit obtained from FAA's Flight Standards District Office in Salt Lake City, Utah, allowed the pilot to ferry the airplane to Durango. According to the pilot, law enforcement officers would not permit him to take off on Colorado Highway 141, but would allow the takeoff from an intersecting county road. The pilot said the road was narrow with powerlines alongside the road and crossing at irregular intervals. He examined the roadway and determined he could depart safely. Traffic was halted in both directions. During the takeoff roll, the airplane's left wing struck a 4"x4" post supporting a speed limit sign.