As school districts across New Jersey struggle to make ends meet, a growing number of them are placing ads on the sides of their school buses in an effort to raise additional revenue.

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About 20 districts in New Jersey have ads on their buses, and several more are considering the idea, according to the New Jersey School Boards Association (NJSBA).

"The money received from school bus advertising has to go toward fuel costs and also classroom purposes," said Frank Belluscio, executive deputy director of the NJSBA.

Legislation was passed in 2011 that enabled districts that own or lease their buses to place ads on them.

There are restrictions, however, on what ads can be placed on school buses.  According to Belluscio, political endorsements are not allowed.  Also not permitted are ads pitching certain substances such as tobacco and alcohol.

He stressed many of the people who will be seeing the ads everyday are children.

"Many school boards don't feel the children should be exposed to advertising, but there's others that don't find it objectionable. They feel the revenue is worth it. It really comes down to the revenue advantages over the exposure of the children to advertising," Belluscio said.

This is not the first time this type of issue has come up.

In the early 1990s there was a program called Channel 1, which provided educational programming via satellite television to school districts, but part of the agreement required commercials to be aired during those programs.

"Many of the districts were opposed to having the commercials during class times, but other districts felt the advantages of having this type of technological equipment in their schools outweighed that concern," Belluscio said. "It was a decision made locally, and we're seeing the same sort of situation now with school bus advertising.", a group that helps districts find advertisers, estimates profits from school bus ads have generated close to $350,000, with each ad on a single bus bringing in about $500 annually.