New subway construction in New York City is both significantly pricier and less prevalent than in peer cities across the country and the world, according to a new report.

Cities like Madrid, London and Paris are building out many more subway track miles at a fraction of the cost that’s seen in New York, the Regional Plan Association said in the report, joining a chorus of experts who fear that the unusually high construction expense in the city could hurt the development of future subway projects.

“We all know that New York’s costs are astonishingly high and the time required for construction astonishingly long,” wrote Julia Vitullo-Martin, a senior fellow at the RPA. “We know that the public is skeptical of New York’s ability to deliver major capital projects. We know we’re not going to get more transportation construction, however crucial to the city’s development, unless costs are brought down and procedures streamlined.”

Between 1999 and 2023, Madrid will have built 71 miles of underground railway at the cost of $3.5 billion. London will have 48 miles of new underground rail at $31 billion. New York will have 13 miles at $19.9 billion — barring any future delays of the Second Avenue subway, of course.

When looking at total route miles of various rail projects, both Denver and Los Angeles far surpass New York over the past 10 years as well.

The first three stations along the Second Avenue line alone cost $4.5 billion to build, ranking it as “the most expensive subway extension on the planet,” according to the RPA.

The MTA did not respond to a request for comment, but executives have in the past pointed to the city’s complexity of underground infrastructure as one of the main drivers of spiraling costs.

Without managing costs, experts believe the continued expansion of the Second Avenue subway line could be in jeopardy. The line’s second phase, which will extend the Q train up to 125th Street in Harlem with three more stations, will cost $6 billion to build, according to preliminary MTA estimates.

About a third of that cost, $2 billion, will need to come from the federal government, which has not yet publicly shared local officials’ fervor for the project.