Investing in transit projects is expensive, but doing nothing to address growing gridlock would prove even more costly to the Twin Cities economy.

That’s the thought Minnesotans should keep in mind as they consider the nearly $500 million increase in the estimated cost of the proposed 13-mile Bottineau light-rail line (also called the Blue Line Extension) that would travel from Target Field in downtown Minneapolis to near Target’s corporate campus in Brooklyn Park.

The revised $1.48 billion price tag is not the result of any mismanagement by the Metropolitan Council, which would build and operate the line. The higher cost reflects the additional data now available after 15 percent of the engineering and environmental work has been completed. Previous estimates were based on just 1 percent of that work being finished. Much of the spike is due to added infrastructure, including seven new bridges and an additional station. There’s also more mitigation needed for areas with wetlands or contaminated soils. Other factors include incorporating the project into an Olson Hwy. redo, as well as the need for more light-rail cars. Inflation plays a factor, too. Funding would come from the Federal Transit Administration (49 percent), the Counties Transit Improvement Board (31 percent), Hennepin County and the state (10 percent each).

The state share appears to be the most problematic. In fact, the Legislature has not fully funded the 10 percent for the proposed Southwest light-rail line (also called the Green Line Extension), which is further in the development process than Bottineau. The 2016 session may be a make-or-break time for Southwest, and that outcome could impact Bottineau as well.

Meanwhile, business leaders have identified workforce development as their key challenge. The next generation of talent has multiple options on where to grow careers and families, and surveys have repeatedly shown that transit options are important to this group. The Twin Cities area has fallen behind peer regions such as Denver and Seattle in transit investment. And anyone familiar with driving in the metro area these days knows that growth cannot be accommodated with a status-quo system.

Most Republican lawmakers oppose light-rail expansion, arguing that ridership is too low to support the investment. They should listen more closely to their constituents in business, who counter that this region needs a healthy transit system to compete.

Those legislators who flatly reject rail need to offer alternatives that go beyond simply adding more lanes. Those who have voiced support for bus-rapid transit (BRT) as an alternative should offer a vigorous funding and implementation plan. Gov. Mark Dayton told an editorial writer that he’ll ask the Met Council to review other ways the Bottineau corridor could be served. But, he cautioned, the status quo should not be an alternative.

“The cost of doing nothing — in terms of opportunity costs, in terms of congestion, travel times, accidents, everything else — I just know would be multiple times the cost of the Bottineau line, and therefore the Bottineau line is essential, or something like it,” Dayton said.

The existing Blue and Green LRT lines have strong and growing ridership numbers. Extending them to promote economic growth — or finding effective alternatives — would be a long-term investment in the region’s vitality.