NASHVILLE (AP) - State troopers will be targeting traffic violators in school zones as classes resume across Tennessee.

The speed limit is 15 mph in school zones and the fine for speeding in such a zone is up to $500. It also is against the law to pass a school bus when it is stopped and loading or unloading passengers; fines for that are no less than $250 and up to $1,000.

In 2011, state troopers issued almost 3,900 citations in school zones, up from 3,200 a year earlier.

THP Col. Tracy Trott said motorists who are distracted, impatient or careless can expect a stiff penalty for driving unsafely in school zones.

Six-hundred thousand children ride school buses in Tennessee.