The Times of Swaziland reported today that the man appeared in court yesterday was charged with negligent driving. He remains in police custody.
The newspaper said the 46-year-old man is a driver employed by the government of Swaziland.
The girls and young women were killed while on their way to join thousands of others at Swaziland's most famous traditional festival, the annual reed dance.
A rights group, the Swaziland Solidarity Network, claims that the death toll has risen to 65. Swazi police dispute this, saying that only 13 people died.