Major upgrades to one of the Twin Cities region’s busiest bus routes, running through the heart of north Minneapolis, are being pushed back another year partly due to funding constraints.

The Penn Avenue rapid bus project is expected to speed bus times by 25 percent through wider stop spacing, traffic signal priority, preboarding payment and curb modifications. Riders would be treated to robust stations featuring heat, lighting, and real-time arrival information.

The first of these concepts, known locally as arterial bus rapid transit, will roll out in June on Snelling Avenue. But the Penn Avenue line, previously on track for 2017 construction, will have to wait another year to 2018.

The line would run from downtown Minneapolis to Brooklyn Center, with buses every 10 minutes. It would open in 2019 under the new timeline.

Katie Roth, who oversees arterial bus rapid transit at Metro Transit, said money is one reason for the change. The project is $15 million short of its $30 million to $35 million budget.

One challenge paying for local bus improvements — vs. light rail lines — is that they are not funded through the quarter-cent sales tax administered by five metro-area counties.

But there are benefits to the delayed timeline, Roth said. It would allow the bus project, known as the C Line, and accompanying intersection redesigns to occur in conjunction with planned 2018 road work on Penn Avenue and Brooklyn Boulevard.

“Rather than rushing to open the C Line only to find ourselves mired in construction impacts from other projects, we’re going to be pushing the project out a year to better align with other work,” Roth said.

The project’s construction date has changed several times. It was originally slated for 2017 construction. In 2014, Metro Transit eyed a 2016 construction date by redirecting funds from a similar project along West 7th Street in St. Paul, which had stalled.

But the body that distributes the region’s federal funding, the Transportation Advisory Board, did not approve that move. The bulk of that federal money went to service improvements on other local routes, as well as a highway underpass and future suburban bus service.

About 7,000 people a day ride the Route 19 along Penn Avenue, the seventh busiest bus route in the region. That bus carries 25 percent of all people traveling along the corridor, but comprises 3 percent of vehicle traffic.

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