A company that has come under fire for aggressive enforcement policies at its parking lots in Portland will relax its practice of booting vehicles with expired parking tickets.

Asher Chappell, a partner and manager with Unified Parking Partners, said Wednesday that the company will issue notices to drivers the first three times they overstay their paid time, instead of booting their vehicles.

“If your (parking) ticket has expired, we will write them a ticket,” Chappell said. “After three unpaid tickets you will be subject to a boot.”

A driver who receives a “ticket” from the company, which does not have legal authority to issue tickets as the city does, will have 10 days to pay it off before it is turned over to Unified Parking Partner’s collections department.

The new policy went into effect Wednesday at the lots managed and owned by Unified Parking Partners, which will continue to boot drivers who don’t pay to use its lots.

A sign at one of the company’s lots near City Hall states, “Tickets will be issued for anyone exceeding their purchased time. Tickets are $20 for each violation.” The sign goes on to say that tickets that are not paid in 10 days will double and that an additional ticket will be issued every two hours vehicles remain in violation.

“We’ve tweaked our policy for those customers who pay,” Chappell said. “We feel this is a very fair policy, that it is a little more customer friendly. What doesn’t change is that we still expect people who use our lots to pay.”

Unified Parking Partners made a splash in Portland last year, when it took over management and enforcement for private parking lots downtown. It now owns and manages more than 6,000 parking spaces in Portland, including 3,000 pay-and-display spaces. The company has 40 lots and garages in Portland, including 16 pay-and-display lots downtown. Many are privately owned and closed to the public during the day, but are open on nights and weekends.

Unlike parking lots that collect a flat rate when vehicles enter or charge by the hour when they leave, Unified’s lots require customers to prepay for the time they need, often using automated kiosks. They display their parking tickets on the vehicle’s dashboard.

The company opened up thousands of parking spots that were off limits to the public, but aggressive enforcement that included booting – placing a large metal clamp on a vehicle’s tire – prompted outrage from visitors and residents.

Critics criticized the company for charging as much as $70 to have the boot removed.

In the past, the company has granted paying customers who have exceeded their time limit a 20-minute grace period before booting their vehicle. Chappell said the grace period is being eliminated under the new policy. It will still cost parkers $70 to have a parking boot removed from their vehicle.

“We are constantly re-evaluating our parking policies to make sure they reflect what is happening on the city side,” Chappell said of what prompted the policy change.

Portland’s parking policy allows the city to boot a vehicle with three or more outstanding unpaid tickets, according to the city’s website. In order to get a boot removed, the owner must pay all unpaid parking tickets, plus a boot fee of $50.

The city also has the option of towing a vehicle for having three or more unpaid tickets. If you are towed, you must pay the city all outstanding tickets, fees, fines and penalties before your vehicle can be returned. The city towing fee is $85.

Critics of the company had complained that its use of the blue “P” sign was misleading. That symbol is universally recognized as denoting public parking, but in Portland it had largely been used for municipal lots and garages.

Parking on city streets and lots is free on Sundays, holidays and between 6 p.m. and 9 a.m., but the company charges for parking throughout the nights, weekends and holidays.

The company has defended its practices and worked with the city to improve its signs, as well as rolling out a mobile app that allows people to purchase additional parking time through their smart phones. Even so, complaints continued.

In March, art groups said that the lack of free parking was hurting attendance and creating an unpleasant experience for art lovers and theater-goers.

After being inundated with complaints by people thinking the city was booting their cars, the City Council passed an ordinance in November requiring the company to update its signs to ensure drivers knew they were parking in a private lot. The ordinance also requires these companies to pay a $100 licensing fee and its owners to pass criminal background checks.

Unified Parking Partners owner Daniel McNutt, 38, of Falmouth was subsequently arrested and charged with possession of cocaine shortly before midnight on May 14 in a parking lot next to City Hall that is managed by the company. He is scheduled to appear in court July 7, according to officials at the Cumberland County Jail.