An attendant flags cars into the In Town parking lot at the corner of Mathewson and Chapel streets in downtown Providence. The city’s growing popularity is pushing up the price of parking at many lots.

THE PROVIDENCE JOURNAL FilesGLENN OSMUNDSON

PROVIDENCE — The Rhode Island Convention Center Authority is planning to hike the cost of parking at its downtown garages, saying the rates have remained low despite steadily rising demand.

The size of the proposed rate change has not been set, but the coming increases will impact a broad swath of motorists who travel to Providence for work, shopping, dining, sporting events or activities such as WaterFire. That’s because the convention center controls 2,515 parking spaces in three lots, or nearly 40 percent of all downtown parking.

New boutiques, luxury housing, office buildings and cultural activities have been luring visitors to downtown Providence, powering an economic boom welcomed in the virtual city-state.

But motorists navigating the Renaissance City are beginning to pay the price for that success, surprised as much by the steep parking prices as by the new high-rise condominiums sprouting on both sides of the river.

For big events, such as the recent Elton John show at the Dunkin’ Donuts Center, the convention center garages charge $20; at nearby lots, parking attendants waving fluorescent-colored flags advertise spaces for as much as $30 on busy nights.

“The parking situation down here is horrible,” said Carol Giovanni, 44, a clerk at the Providence Cookie Co. at the Arcade mall, who delivers muffins to customers idling on Weybosset Street so they can avoid hunting for a spot. “It’s crazy, but what are they going to do, drive around in circles like we do?”

The planned rate hike at the convention center was prompted by a study — commissioned in February by the convention center authority, an independent government agency — comparing the public parking lots to all competitors in a 1,200-foot radius. The findings revealed a marked disparity, with the owners of private lots taking greater advantage of the rapid redevelopment of the downtown district.

“There’s room for us to capture some more revenue,” said Timothy Muldoon, general manager of the convention center. “We have been pretty conservative as far as our increases, but I think we can demand more now.”

The proposed increases, under review by an authority committee, will be considered by the full board on April 26.

The median price for a half-hour of parking downtown is $6, $2 more than it costs at the convention’s two garages, according to the study by Chicago-based Walker Parking Consultants. The convention center’s $8 event parking price is also $2 below the going rate, and its monthly charge of $135 is $22.50 below average, the study found.

Muldoon insists the convention center has no plans for price “gouging.” The parking rates, he said, have rarely changed since the convention center garages opened in 1993, despite the growth in economic activity in Providence.

A year ago, the monthly rate was raised $14, the first increase in at least three years. The daily parking rate has not changed since 2003, and the cost for general event parking has gone up just $2 in 14 years.

Any increase would be financially significant for the authority. Last year, the parking garages generated $4.1 million, almost one-third of the convention center’s income. The money is used for operating expenses at the convention center and civic center, and for repaying the taxpayer-backed loans that paid for the buildings.

Non-event parking at the convention center is already more costly than at some of its competitors in New England.

In Worcester, for example, parking at the 1,000-space garage at the DCU Center costs $8 a day, compared to $16 in Providence. Monthly parking is $120, 11 percent less than at the Rhode Island Convention Center.

A municipal lot near the Verizon Wireless Arena in Manchester, N.H., charges $45 a month for a space. In Portland, Maine, parking at the Cumberland County Civic Center costs $12 a day, or $90 per month.

“Providence is going through a real renaissance, and whenever that happens you tend to see parking rates go up,” said Andy Hill, of Walker Parking Consultants.

The convention center authority says its low rates have helped slow that trend in Downcity. Prices here are significantly below larger downtowns on the East Coast, including Boston and Manhattan, where the median monthly parking bill is $420 and $574 respectively.

Parking in Hartford is also more expensive than in Providence. The Hartford Civic Center, for example, brings in $30 a day from daily customers and $235 from monthly parkers.

Not all changes to the downtown have inflated parking prices. Though downtown construction has eliminated some surface lots — several hundred spaces were lost near the train station to a condominium project — high parking prices have led to fierce competition among garages, particularly since the Providence Place mall opened in 1999. (The mall garage has 2,250 spaces, priced at $1 for the first three hours, $25 a day or $160 a month.)

Also, downtown garages lost customers when the state relocated offices to Cranston, and when the new Kent County Courthouse opened in August, relocating cases that once brought lawyers and defendants to Providence, according to former Providence Mayor Joseph R. Paolino Jr., whose Paolino Properties owns several parking lots.

But by some measures, parking in Providence is already unusually costly.

The median monthly rate in Providence is above the national average, according to a study of 51 markets by Colliers International, a real estate consulting firm in Boston. The 2006 study calculated the national median monthly rate at about $154, $3.50 less than it is here.

Downtown parking lot owners say an increase at the convention center would not have a significant impact on their prices. That’s in part because they are thriving despite significantly higher rates, says Charles Meyers, president of Metropark Limited, which owns or operates 350 spaces in Providence, including a Pine Street lot that rents spaces for $250 a month or $20 a day.

The convention center “is a bargain,” Meyers said, “but don’t forget, this is Providence and people don’t like to walk.

“There’s a limited amount of supply, and much bigger demand,” he added. “There’s been a lot of people who have moved into the city.”

In the past year, employees at GTECH Holdings Corp.’s new downtown headquarters have leased about 200 spaces at the convention center. Large construction crews at the Westin and elsewhere have boosted early bird parking receipts there by 57 percent since July of last year.

Sean Marchionte, who controls 700 spaces as president of City Parking & Valet Services, said prices are also affected by the rising value of downtown real estate. As leases for garage operators become more expensive, he said, the added cost is passed on to customers.

William Ashworth, who has researched Providence parking for the consulting firm Vanasse Hangen Brustlin Inc., said increases in the price of parking could spur the development of better public transportation for a city with no subway or commuter rail connections to most of the state.

But other experts say that higher priced parking leads to increased traffic, as motorists endlessly circle city streets looking for less expensive metered spaces. In Providence, meters cost $1 per hour.

Even without the proposed increases at the convention center, many motorists are already complaining about the cost of parking downtown.

Sue Giannini, 39, of Cumberland, said she spotted parking lots charging $40 during a Britney Spears concert. “The city looks cleaner,” she said, “but forty dollars to park for an event is ridiculous.”

bgedan@projo.com