A school bus idles at Wakefield High School in Arlington. Officials were demonstrating cameras aimed at catching motorists who illegally pass school buses when the stop arm is deployed. (Moriah Balingit/ The Washington Post)

Arlington County is throwing out tickets issued to motorists who were caught on enforcement cameras as they illegally passed school buses during the past two months — and the county might issue refunds to those who have already paid — after Virginia Attorney General Mark R. Herring’s opinion that officials do not have the authority to send the summonses by mail.

The city of Falls Church, which issued 995 citations to drivers caught on school bus cameras during the past two school years, has no plans to issue refunds in those cases.

Motorists who have not paid their fines are advised to call city police for a review of the tickets on “a case-by-case basis,” said Marybeth Connelly, a Falls Church City Public Schools spokeswoman.

The opinion by Herring (D), published this month, led Arlington and Falls Church to shut down their bus-camera programs because the guidance requires officers in Virginia to deliver citations by hand to drivers’ homes. That proved too burdensome for both departments.

The opinion also has delayed the implementation of school bus cameras in Albemarle County and could spell the end of the programs in the state if the law is not changed.

“Attorney General Herring certainly wants to keep our kids safe around school buses, and enforcement is an important part of that, but the General Assembly just hasn’t yet authorized these summonses to be issued by mail,” said Michael Kelly, spokesman for the attorney general.

The 2011 state bill that provided for bus-camera enforcement originally had a provision to allow for the tickets to be mailed. But that was stripped during the legislative process. Kelly said the attorney general would urge lawmakers to add back the provision.

“This opinion has identified a flaw in the law, and Attorney ­General Herring will work with the legislature to close this ­loophole so Virginia can crack down on these dangerous drivers,” Kelly said.

Across the country, the cameras have become a way to deter motorists from driving around school buses, which police say endangers schoolchildren as they enter and exit the vehicles.

School districts that use the cameras have reported a deterrent effect, with fewer cases of vehicles passing school buses when they are stopped, in part because of public awareness campaigns. Some worry that shutting down the programs will mean more violations and more children being put in danger.

“The reason we put the cameras on buses is because motorists were not stopping for buses with the stop arms deployed and [were] endangering the lives of students,” Arlington Public Schools spokesman Frank Bellavia said this week.

The violation is difficult to ticket because it requires a police officer to witness the offense or a bus driver to record the license plate number of a passing car as they are also keeping track of schoolchildren.

The cameras capture images of every vehicle that passes a school bus as it unloads passengers.

Arlington police issued 236 in-person citations to motorists driving around school buses during the past school year. In the first two months of the program this year, police issued 216 mail summonses.

Of the 216, 31 motorists have paid their $250 fines, and attorneys for Arlington schools are reviewing whether to issue refunds.

The other 185 tickets were dismissed, and violators who received them have been sent follow-up letters telling them not to pay.