You wanted to know why the state was doing that. We Heard You and did a little digging.
The Illinois Department of Transportation looked into the issue. The rest stop is off I-74 between Farmer City and LeRoy. IDOT says crews were only watering the grass around walkways.
There was a concern someone smoking might accidentally start a fire. It was just enough water to keep that from happening. They weren't doing the entire lawn.
Since then, IDOT has stopped the watering all together. With the upgraded drought conditions and water restrictions, Friday was the last day.