The 51-year-old who was driving the bus when it caught fire on the A2 near Hannover, said it was a sea of flames within seconds, trapping all of the passengers in the back of the vehicle.
“All those who survived were sitting in the front rows,” he told the Hannoversche Allgemeine Zeitung on Sunday.
He said there were no flammable materials on board, and he had not used any dangerous cleaning fluids in the bus.
The cause the country's worst bus accident in 16 years is still under investigation, although reports suggest a technical defect in the toilet could be to blame.
The vehicle was carrying mostly elderly day trippers on the way home on November 4 when the bus went up in flames. Twenty people including a 13-year-old girl were killed, and 13 more injured, some severely.
“Within two minutes the bus was so full of smoke and flames that you could not see into the back part of the bus – absolute death. Everything was dark, there was nothing more,” the driver told television show RTL Extra in an interview to be broadcast on Monday.
He said he had looked at the back door to see if anyone could get out, but said, “Apart from flames, there was nothing more to see.”
The man, who was deeply traumatized by the accident, said he was particularly dismayed that no-one on the autobahn stopped to help.
He said, “I jumped out into the autobahn, and waved my arms, but no-one stopped – not one car or lorry stopped for me.”
Other reports confirmed that only a few people offered to help at the accident site, and that one person even filmed the burning bus rather than offer help.
The film, taken on a mobile phone, was later sold to a news programme. The state prosecutor is investigating whether charges could be brought against the man for failing to help.