Seven people in an overloaded van died Saturday when the vehicle skidded into a ravine in the southern Guangxi Zhuang Autonomous Region, Xinhua, the official government news agency, reported.
Twelve people were killed in southwestern Guizhou province when a bus veered off the road and down a steep slope.
Eighteen people died Friday night when a bus caught fire after falling into a ravine in Gansu province in the northwest. Eleven people died in a bus crash in Sichuan when the driver veered off the road.
Scores of people were injured in the four crashes.
A truck carrying fireworks exploded Friday on a highway viaduct in Henan. Ten people were killed when part of the viaduct collapsed.
The Spring Festival -- which culminates with the Lunar New Year, occurring Feb. 10 this year -- is the busiest travel period in China, with millions of people heading to family celebrations.
This year, 3.4 billion people are expected to make journeys during the festival, with most of them traveling by bus and 225 million by train.