On August 8, 1993, at approximately 2140 central daylight time, a Cessna 177B, N34293, sustained substantial damage near Grand Prairie, Texas, during a forced landing following a loss of engine power. The private pilot, a private pilot rated passenger, and the two other passengers were not injured. Visual meteorological conditions prevailed for the personal cross country flight. Interviews, conducted by the Federal Aviation Administration (FAA) inspector, and the investigator in charge with the pilot revealed the flight originated from Olathe, Kansas, at approximately 1748 on an IFR flight plan to Grand Prairie, Texas. An emergency was declared by the pilot when a total engine power loss occurred enroute at 3,000 feet MSL and approximately 12 miles from the destination airport. During the landing on an interstate highway, the right wing of the airplane hit a road sign. The airplane subsequently impacted a construction barricade and came to rest nose down on the north shoulder of the interstate. The Grand Prairie city fire department reported to the investigator in charge that a vehicle, braking to avoid hitting the airplane, received damage as it impacted the center median. The driver and three occupants of the vehicle were not injured. An examination by the FAA inspector revealed physical evidence of the fuel pressure line leaking. The line was changed and an engine test run was conducted with no anomalies. The airplane was released to the owner's representative following the investigation.