Söderledstunneln, a highly-trafficked tunnel between two islands in central Stockholm, was shut down early on Thursday morning after heavy smoke forced about 50 vehicles to back out.
"The tunnel is busy even at that time of day, and when we arrived we shut down the entire thing," said Stockholm police Jonas Torelli. The tunnel spans 1.5 kilometres.
Police were able to locate and extract the burning car around 4:30am, and discovered that there was no one in the vehicle.
"The owner said he was clueless and thought the car was parked outside his house," Torelli said.
Police said no one was harmed in the fire.