The Metropolitan Transportation Authority could dramatically reduce its sky-high construction costs by rethinking how it manages projects, prioritizing efficiency over bureaucracy and ending rules that require far more workers than are needed, according to a new report based on two years of research.

The report, scheduled to be published on Tuesday by the Regional Plan Association, an urban research and advocacy group, says that dozens of missteps, abuses and inefficiencies have helped to make New York City the most expensive place in the world for public transit projects.

Among other factors, the report’s authors found that recent megaprojects like the first phase of the Second Avenue Subway on Manhattan’s Upper East Side have suffered from overly burdensome environmental reviews, repeated political interference, out-of-date work rules, “excessive customization” and a lack of coordination, communication and accountability.

“The extraordinarily high costs are due to many factors at every stage, from decisions by political leaders at the inception of a project to the final stages of a lengthy process of planning, design, and construction,” wrote the authors, Richard Barone, Julia Vitullo-Martin and Alyssa Pichardo. “Long tolerated as an accepted natural consequence of New York’s size and dominance, these costs threaten to strangle New York’s future economic growth.”