Wet weather in Waikato has prompted police to urge motorists to drive to the conditions.
There were 11 crashes after it rained in the region last night, with two resulting in serious injuries, and at least 15 crashes today.
In one crash, the driver of a van lost control exiting Cobham Bridge and crashed into two vehicles.
Police said following distances needed to be increased from the two-second rule, to at least four-seconds.