Adding a new type of transit along the Riverview Corridor between downtown St. Paul and the Mall of America could cost hundreds of millions to well over a billion dollars, but the higher price tag options often come with higher ridership.

New projections give local officials multiple choices — light rail, different types of bus rapid transit, a streetcar or sticking with local bus service — along four different routes. But officials are still seeking more information for the complex project, which has at times drawn sharp neighborhood opposition.

They are expected to select the route and type of transit by the end of this summer. But whatever option they choose won't be up and running for a long time.

"Most of us might not be here when it's all said and done," Ramsey County Commissioner Rafael Ortega told about 80 people gathered for an information session on the line Wednesday night in Highland Park.

He said they are creating the line for their children and need to look at projected growth in the neighborhood. By 2040, there will be 32,000 new residents along the Riverview Corridor, he said.

Ortega is a member of the corridor's Policy Advisory Committee, which will review the projections in April, along with other criteria, like community and environmental impacts and safety.

The cost estimates, which do not count for inflation, show bus rapid transit is the cheaper option. But the average weekday ridership for the various routes would be 12,725 in 2040 if officials select that type of transit.

Light rail or streetcars, on the other hand, would cost roughly twice as much as bus rapid transit but would draw an average of 19,350 riders.

By comparison, people took 30,337 rides on the Blue Line light rail on a normal weekday last year and 4,521 on the new A Line bus rapid transit.

On Thursday, the Policy Advisory Committee pushed back the time frame for gathering public input and selecting a route and transit type. The committee's discussion offered a glimpse into the project's complexity — and why it has taken nearly twice as long as expected to come up with a preferred option.

Committee members asked for more information on a bus rapid-transit route that stops at Fort Snelling and the airport's Humphrey Terminal. Mike Rogers, with the Ramsey County Regional Railroad Authority, said they did not include that route option in the projections because it would add 11 minutes to the trip and result in a 10 percent drop in ridership. But committee members said they didn't want the public to feel like they haven't explored all the options.

They decided to pay the estimated $100,000 additional cost and delay the process by up to three months to get an analysis of the alternative. Regional Railroad Authority staff members said they now plan to gather public input on the options this summer and will have a preferred option drafted by August or September, at the latest.

There have already been many community meetings about the line. Some have featured a lot of frustrated residents who oppose the project — particularly rail — but this week's audience in Highland Park was more supportive.

Tyler Blackmon said he lives in an apartment along W. 7th Street and uses his car to get around, but would like better transit options. Many of his neighbors in the apartment complex work at the airport, he said, and would benefit from a light-rail line on the street.

"Anything less than light rail is really doing us a disservice," said Blackmon, who wants the neighborhood to connect to the growing metro network of light-rail lines.

Larry Pfaff, a Highland Park resident and user of the A Line bus rapid transit route, said he would like a similar option along the Riverview Corridor.

"We've got a hell of a lot of things we ought to do with our money," Pfaff said, and bus rapid transit is less expensive than rail and would allow for more spending on other projects. Pfaff was wary of the streetcar option, which he said feels "unproven."

Some Policy Advisory Committee members traveled to Kansas City last month to check out that city's streetcar, which runs on a 4-mile loop downtown. Trip attendees gave the streetcar good reviews, saying it boosted business and had widespread support.