The Colorado Department of Transportation says a bus carrying 50 people crashed into a median south of Walsenburg on I-25.
The crash happened 4 miles south of Walsenburg early Thursday morning.
Colorado State Patrol said the bus was headed north on I-25 when the driver lost control in icy conditions, ran off the side of the road, and flipped.
The driver, 53-year-old Alberto Torres, is charged with careless driving causing bodily injury.
It took a long time to carefully remove all 49 passengers and the driver from the wreckage of the upside-down bus.
Among the passengers - ages 4 to 83 years old - there are minor to life-threatening injuries, but no fatalities.
The passengers with moderate injuries were taken to hospitals in Walsenburg and in Pueblo.
CSP said excessive speed is considered a factor in this accident and it remains under investigation.