Two youths were arrested after they allegedly threw plastic traffic bollards off the top of a shopping centre car park.
The males were caught throwing the missiles from the roof of the multi-storey car park at The Ridings in Wakefield, according to a council report.
One of the bollards smashed the window of a car in which two children were inside, though no-one was injured as a result.
CCTV operators then tracked the youths, before they were detained by Ridings security guards.
The alleged incident, which took place on May 31, was mentioned by Wakefield Council's Cabinet member for communities, Maureen Cummings, in a report which will be approved next week.
A spokesman for The Ridings confirmed no-one was hurt and said the incident was an "isolated" one.
"The safety of all of our customers is paramount," he added.
Local Democracy Reporting Service