A group of business leaders and elected officials gathered Tuesday to support the proposed B Line rapid bus project, which could connect Uptown in Minneapolis to downtown St. Paul.

“The B Line is a very smart investment,” said Ecolab CEO Doug Baker, during a news conference Tuesday. “It will speed up transit greatly.”

Efficient and reliable public transit will help the St. Paul-based company, one of the largest employers downtown, attract and retain employees, he added.

The $54 million B Line would operate on what is now the Route 21 local bus corridor, which mostly travels along Lake Street in Minneapolis and Marshall Avenue in St. Paul to the city’s Midway area. However, St. Paul Mayor Melvin Carter and other transit advocates support extending the B Line’s reach to downtown.

The B Line may replace Route 21, the second-busiest route in Metro Transit’s system — and one of the slowest buses — providing passengers with about 10,000 rides a day. Construction is expected to begin in 2022; Metro Transit has not said when passenger service will begin. To date, $16 million in funding from the federal government and the Metropolitan Council has been identified to help build the B Line.

Metro Transit has pitched an aggressive expansion of the rapid bus system, building on the success of the A Line rapid bus that debuted in 2016. It connects the Blue Line’s 46thStreet station in Minneapolis to Rosedale Center mall in Roseville. Ridership along the Snelling Avenue corridor has increased by more than 30% since the A Line began service.

Rapid bus service is touted as faster and more reliable because it features limited stops and more frequent service. Passengers pay before they board, much like light rail, and heated stations feature real-time schedule information.

The Twin Cities’ second rapid bus, the C Line, is slated to begin passenger service later this year, serving north Minneapolis and the northern suburbs. The Met Council has asked state lawmakers this session for funds to help build the $75 million D Line, which will largely replace the Route 5 local bus, the busiest transit thoroughfare in the state.

Correction: An earlier version incorrectly stated when construction will begin on the B Line.