Police said the Dallas Parks and Recreation Department left the sprinklers on near White Rock Lake.
A driver lost control on the icy road and hit a sign marking the entrance to a parking lot off Northwest Highway and Lawther Drive.
The road was closed and a sanding crew was called in.
A similar thing happened in Highland Park where the sprinklers were left on at a new home construction site.
It made a stretch of Preston Road so dangerous that the city had to spread sand on the street to give drivers some traction.
In anticipation of potential ice and wintry mix over the weekend, TxDOT crews have already pre-treated area roads, coating roads and bridges with brine in advance of potential storms.
Crews have created a salt barrier, which makes it tougher for roadways to ice over.
Dallas, Fort Worth and Frisco schools are asking parents to keep checking social media and district websites for potential closures, but to otherwise assume that classes are still on.