PORTLAND, Maine — Parking calculations headed the list of topics for renewed Planning Board discussion Tuesday about the Forefront at Thompson’s Point.

New data supplied by Randy Dunton of Gray-based Gorrill-Palmer Consulting Engineers better quantified how many vehicles could use the site during peak and evening hours, and it revised calculations of how many parking spaces will be needed.

In a cover letter, Forefront Partners principal Chris Thompson noted the parking can be increased incrementally as areas are completed, perhaps to a maximum of more than 1,800 spaces. He doubted all the spaces would be needed.

Initial plans indicated the combined arena, convention center, restaurant, residential and hotel project would have almost 1,300 spaces, an amount Thompson said is more than needed for average daytime use at the 32-acre site.

Thompson said gaining additional spaces can be achieved through valet parking or even additional parking garage spaces built under planned buildings not yet meeting the 120-foot height limit for the project.

“We had always planned to be able to accommodate, on site, the project’s parking needs at full build-out, assuming a Red Claws game and all other uses at full capacity,” Thompson said.

He noted an existing arrangement with Mercy Hospital adds 320 after-business-hours spaces in a hospital lot off Fore River Parkway, and there is an expectation that as many as 10 percent of the development parking spaces may not be needed because people attending concerts, games and events will arrive by bus or other alternate forms of transportation.

When completed, the project will have to accommodate parking for up to 5,000 people for concerts and 3,500 people for Maine Red Claws games.

The Planning Board is now engaging in master plan discussions without taking up specific elements of the site plan for approval.

As outlined by Dunton, the project contains 13 buildings, including one parking garage and one “ancillary” building that will not generate additional traffic. The development would be built on land jutting to the Fore River, and bordered by Interstate 295. Additional access to the development would come from an extension of Sewall Street to Congress Street.

As reported in the Bangor Daily News, the project would also require widening off-ramps from Exit 5 on Interstate 295, and timing traffic lights at the Fore River Parkway to prevent backups from the highway.

The plan has been discussed for three years. The city granted a $31 million tax break over 30 years and then added three acres of land acquired from Suburban Propane. The company is expected to relocate to city land it will buy off Riverside Street.

The added acreage has also led to plan amendments requiring more Planning Board discussion. Revised master plan drawings and renderings of how the project will look from adjacent streets were also presented.