ALTAMONT — A woman was arrested at Altamont Elementary School yesterday because, police say, she was driving with a blood alcohol level of nearly three times the legal limit.

Grace Gerke, 41, was dropping her 7-year-old off at the school when officer Christopher Laurenzo stopped her at 7:53 a.m. for following too closely and talking on her cell phone, he said.

She registered a blood alcohol content of .20 percent on a breath test, according to Laurenzo; the legal driving limit is .08 percent.

Gerke was arrested under Leandra’s Law, which took effect in December 2009, and makes it a felony to drive drunk in New York with a minor in the car, following the death of 11-year-old Leandra Rosado in an accident on the Henry Hudson Parkway.

First-time offenders charged with driving while intoxicated felonies can sometimes plead down to a charge of driving while ability impaired, a violation, according to Heather Orth, a spokesperson for the Albany County District Attorney’s office, but Leandra’s Law allows defendants to plead down only to a misdemeanor DWI charge.

Gerke was also charged with aggravated DWI, a misdemeanor, for having a blood alcohol content greater than .18 percent. She could not be reached for comment.

Laurenzo said Gerke was arraigned in court yesterday and sent to Albany County Jail until she could post bail. She could not be reached for comment.