The New Zealand Transport Agency is urging farmers in Canterbury to keep a closer watch on what their cows get up to at night.
There have been three road crashes in the area in the past week because of cattle wandering loose on State Highway One.
The agency says all of the crashes happened at night. Although no one was hurt, it says farmers need to be more vigilant about ensuring stock is well contained.
The usual South Canterbury tally for crashes involving cattle is one or two a month.