ASPEN ” The redevelopment of the base of Aspen Mountain will generate 1,300 new car trips a day and as many as 100 vehicles spilling onto nearby intersections within an hour during peak times.

That’s the conclusion made by a consultant hired by two developers who are the driving forces behind what’s known as the Lift One Master Plan, which proposes 300,000 square feet of residential and commercial space along South Aspen Street. David Leahy from Denver-based TDA, Inc. was one of several hired experts who presented details on the development to the Aspen City Council during a public hearing on Monday.

The experts were hired by Centurion Partners and Roaring Fork Mountain Lodge-Aspen LLC, which are individually proposing two hotels, affordable housing, restaurants, retail space and public amenities on an 8-acre site at the base of Aspen Mountain’s west side.

The traffic study is just one of dozens of the plan’s details that have yet to fully be hashed out, though the council plans to vote next Monday on what would be the largest development project Aspen has seen in decades.

The public hearing will begin at 2 p.m. in council chambers on Dec. 8.

Other details of the plan that will get further scrutiny include how the construction will be phased, managed and what buildings will be constructed first.

Council members also are concerned about the developers’ financing and ability to secure loans to build the hotels, as well as pay for the public amenities.

The half-billion-dollar project is estimated to generate only a minimal return for developers, based on a proforma created by Byron Koste, executive director of the University of Colorado’s Real Estate Center.

“The current program yields marginal returns,” Koste told the council, adding that the community benefits that the developers have agreed to pay for have reduced their profit margins significantly.

It’s expected that once the hotels are built and the ownership portions of them are sold, developers might see a percentage of profits in the low- to mid-teens. Most comparable real estate projects net between 30 and 50 percent profit margins, Koste said.

Mayor Mick Ireland said he wants a guarantee, or a deed restriction, on the for-sale units so that they can’t be converted into whole ownership condos and taken out of the rental pool.

Currently, developers propose to provide housing for 75 percent of the employees that will be generated from the developments. However, in response to Ireland’s concerns, John Sarpa representing Centurion Partners and Bob Daniel, representing Roaring Fork Mountain Lodge-Aspen LLC, said Monday they are willing to house 100 percent. The remaining 25 percent of employee housing could be paid for through a special transfer tax collected on the sale of the units in the fractional condominium and membership lodge part of the project.

Public scrutiny is increasing around the development, the site plan and the master plan of the area, which was signed off by a 27-member citizen task force that met weekly from April to September.

However, not all Lift One Task Force members are pleased with the end result.

Denis Murray, a task force member and a resident of the Lift One neighborhood, said the proposal in front of the council is rushed, just as it was at the end of the task force process, when new iterations were presented and minimal thought was given to them.

A proposed surface lift at Dean Street that would take people to a new high-speed quad chairlift, 230 feet farther uphill than the existing Lift 1A, is not adequate accessibility for people wanting to reach the base of the mountain, Murray said.

The plan is flawed and so is the process, he said, adding he was at one time excited about the prospect of creating a vibrant area where skiing in Aspen began and is one of the last pieces of town that remains undeveloped.

“I’m not finding what I had hoped to get in this once-in-a-lifetime opportunity,” he said.

For Cliff Weiss, another task force member and avid skier, the Aspen Skiing Co.’s decision to rely on natural snowfall for the 50-foot-wide swath where the surface lift would be is unacceptable. The whole idea was to get people up the mountain easily and allow for return skiing into town at the end of the day. That’s not possible without a guarantee of snow coverage.

“That is a deal breaker for me,” Weiss said. “Things have changed that I find disturbing …”

While snowmaking might not be feasible in the narrow corridor, Weiss said snowmaking along the World Cup course is and that snow can be pushed to the lower part of the hill once the races, which are traditionally held at the beginning of the season, are over.

Next Monday’s meeting is expected to be the final public hearing on the land-use application. For more details on the plan, log onto http://www.aspenpitkin.com/depts/41/liftoneMP.cfm

csack@aspentimes.com