The bus, carrying Indonesian tourists from Surabaya, the capital of East Java province, was returning from a trip to Central Java’s Dieng Plateau, a popular mountain resort, when it hit the billboard on the Mojokerto toll road just after dawn, East Java traffic police chief Latief Usman said, AP reported.
Television news showed police and medical personnel removing victims from the bus, which crashed just 400 meters (yards) before the highway exit.
Usman said police are still investigating the cause of the accident, but that the driver reportedly appeared drowsy before the crash.
He said police haven’t yet questioned the driver, who suffered severe injuries. Nineteen people were being treated in four hospitals in Mojokerto, mostly for broken bones.
Road accidents are common in Indonesia because of poor safety standards and infrastructure.