The US Transportation Department has opened an investigation into brake problems in the Toyota Prius 2010 model after the Japanese carmaker acknowledged design problems with the brakes in its prized gas-electric hybrid.
The National Highway Traffic Safety Administration told The Associated Press it has received 124 reports from consumers, including four reports of crashes.
The investigation will look into allegations of momentary loss of braking capability while travelling over uneven road surfaces, potholes or bumps.
The Japanese government has ordered Toyota to investigate brake problems.
The company said it had corrected problems with the antilock brake system in Prius models sold since late last month, including those shipped overseas.
The flaw requires a software programming change to fix.