On October 7, 2021, about 0654 mountain daylight time, a Piper PA-24, N5585P, was substantially damaged when it was involved in an accident near Northern Colorado Regional Airport (FNL), Fort Collins, Colorado. The pilot sustained minor injuries and the passenger was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. During takeoff from FNL on Runway 15, pilot reported the airplane was not able to climb normally and that an overspeed occurred of about 2,900 engine rpm. The pilot retarded the throttle, observed a loss of airspeed, and heard a loud bang from near the engine. The pilot executed a forced landing on a road and the airplane impacted a pole, which substantially damaged the left wing. Automatic dependent surveillance-broadcast (ADS-B) data indicated the airplane started to taxi about 0645 and the takeoff roll occurred about 0652. The airplane accelerated to 62 knots groundspeed about 1,800 ft past the runway threshold and the airplane lifted off at 71 knots groundspeed about 3,200 ft past the threshold, which was 5,300 ft from the departure end of the 8,500 ft runway. During the initial climb, about 3,500 ft from the departure end of the runway, the airplane decelerated to 60 knots groundspeed. The airplane flew at 50-60 knots groundspeed and low altitude for the remainder of the flight. About 2,800 ft beyond the departure end of Runway 15, the airplane touched down on a paved road at 59 knots groundspeed. Initial propeller strike marks on the road were 1.17 ft apart, which calculated to an engine speed of about 2,554 rpm at touchdown. Postaccident examination of the airplane revealed no evidence of mechanical anomalies or malfunction. The propeller governor was bench tested and met manufacturer specifications. The pilot reported the airplane’s takeoff weight was about 300 lbs below the maximum gross weight. Manufacturer performance data indicated a takeoff ground roll with no wind of about 1,900 ft at maximum gross weight. During the engine runup before takeoff, the pilot reported pulling the carburetor heat lever out “for a few seconds” and that the engine ran “a little rough” during that period. Review of the icing probability chart contained within Federal Aviation Administration Special Airworthiness Information Bulletin CE-09-35 revealed the atmospheric conditions at the time of the accident were "conducive to serious icing at cruise power.” The pilot recalled setting the mixture lever “about a finger” width toward the lean position for the takeoff. Following the accident, the pilot stated that he should have aborted the takeoff due to the airplane’s slower than normal acceleration.