Police said the "serious crash" occurred on the Taieri River bridge on State Highway 1 at Otokia, near Henley about 5.15am.
Sergeant Matt Lee, of Dunedin, said a 39-year-old man was driving south in a van with three passengers when he lost control due to black ice.
The vehicle spun out and hit the bridge barrier, knocking concrete several columns out. The vehicle stayed on the bridge, but lost all power.
A 50-year-old man in a following truck tried to take evasive action but couldn't avoid hitting the van. Sgt Lee said the man’s manoeuvre may have prevented critical injuries.
The driver of the van called emergency services and was trapped in the vehicle until they arrived.
St John later said it sent two ambulances and four people were taken to hospital. One person was in a serious condition, two were moderate and one person had sustained minor injuries.
The highway was closed for several hours but reopened after midday.
Another crash took place in the same road at 11.50pm on Monday. Sgt Lee said a 25-year-old man hit a patch of ice on the bridge and struck the barrier, which sent him into a spin.
The front of the vehicle was damaged and the left lane was blocked for about two hours before a tow truck removed it.
The bridge barrier was damaged in the crash, but there were no reported injuries.
A police spokeswoman said there were more than 30 crashes in and around Dunedin overnight, ranging from cars sliding down hills into lamp posts through to more serious crashes.
- additional reporting ODT Online
