Story highlights

NEW: Alice Walton refused a breath test, a trooper says

The Walmart heiress is reported to the 10th richest person in the United States

She was arrested last week on suspicion of driving while intoxicated

"She accepts full responsibility," her attorney says

CNN  — 

Walmart heiress Alice Walton, who was arrested on suspicion of driving while intoxicated, “accepts full responsibility” for the incident and “deeply regrets it,” her attorney said Friday.

A Department of Public Safety trooper stopped Walton for speeding in Parker County, Texas late Friday.

“Ms. Walton was pulled over by a patrolman with the Department of Public Safety for driving 71 miles per hour in an unattended 55 miles per hour construction zone. She was returning home from a birthday dinner with friends at a Ft. Worth restaurant,” according to a statement released by her attorney Dee J. Kelly.

“She accepts full responsibility for this unfortunate incident and deeply regrets it,” it read.

Walton was driving a silver Lexus when she was stopped on Interstate 20, according to Texas Department of Public Safety trooper Gary M. Rozzell.

She refused a breath test, but was administered a field sobriety test, which indicated she was intoxicated, he said.

Walton, who Rozzell described as courteous, was then transported to the Parker County Jail. She was released Saturday morning after posting $1,000 bond.

Walton, believed to be worth more than $20 billion, was listed as the 10th richest person in the United States in the September edition of Forbes magazine. She was celebrating her 62nd birthday.