JoAnne McNamara felt like she was operating a steamroller for the city when she drove her Pontiac Vibe down Hertel Avenue on Thursday.

Buffalo’s pothole brigade made stopgap repairs, using an asphalt binder called “cold patch” to fill some holes along the 600 block of Hertel.

McNamara saw the truck ahead of her, and she was stunned when the crew left small mounds of asphalt protruding from the street. The crew didn’t use rollers or shovels to pound the asphalt and stone mixture into the openings.

It was clear that the crew “just expected the cars to flatten out the newly tarred holes,” she said.

McNamara, a freelance photographer, snapped photos of the small mounds, some of which were almost three inches high. She said passing motorists encouraged her to take photos by honking their horns in approval as she pointed to the patches.

“It’s totally disrespectful of anyone who has a vehicle — vehicles that cost thousands of dollars,” the Niagara Street woman lamented.

She said she heard the sound of asphalt coming from the tires and underbody of her car nine hours after her encounter.

“Instead of the thump, thump, thump of potholes, now it’s tar, tar, tar,” she said.

City Hall received one complaint about the work on Hertel, Public Works Commissioner Steven J. Stepniak said. The crew was later questioned, and Stepniak said he’s convinced it was an isolated situation. A crew member told authorities the truck was merely “repositioning” itself from an awkward spot on a busy street and that it returned to flatten out the piles of asphalt.

But Stepniak said a memo will go out to all pothole crews insisting that they make sure cold patch is pounded into crevices before leaving all repair jobs.

“There’s no excuse for not at least tapping that down with a shovel before they move on,” said Stepniak.

The worker involved in the Hertel incident is one of the department’s best employees, said Stepniak.

“I think this was just a guy trying to do his job quickly and making a mistake,” the commissioner said. “We apologize to the motorists.”

McNamara said she pulled into a nearby police station and monitored the situation. She said a city truck showed 15 or 20 minutes after the holes were filed.

“But by that time, everything had already been flattened by passing cars,” she said.

McNamara has yet to have her car’s underbody checked for any problems, but she said she doubts she will file a claim against the city. Her motive in bringing attention to the situation, she said, is to make sure that the practice is halted. In addition to causing possible damage to cars, having mounds of asphalt lining streets can cause safety hazards.

“A few cars who saw them were trying to dodge them,” she said.

The number of pothole complaints is about average for this time of year, Stepniak said. According to data compiled by Citizens Services, 119 pothole complaints were lodged since Oct. 1.

In early 2007, Mayor Byron W. Brown instituted a 48-hour pothole “repair guarantee.” With few exceptions, city officials said potholes are being filled within two business days of being reported. People can alert City Hall to pothole woes by calling the 311 non-emergency number, or 851-4890.

They can also go online at www.city-buffalo.com, click the 311 Call and Resolution Center, then go to the streets section.