Back in 2008, the Congress for New Urbanism released its first report in its ongoing series, Freeways Without Futures. The report looked at 10 highways that were reaching the end of their designed lifespan and were being targeted by local activists for teardowns. Of those, three have successfully been removed 16 years later: Seattle’s Alaskan Way Viaduct, the Sheridan Expressway in the Bronx, and Route 34 in New Haven, Connecticut.

What separates those effective highway removal campaigns from those in other cities? “There are some common threads and lessons that local leaders and activists can learn from to turn their endangered highways into extinct highways,” says Dave Amos, Cal Poly city planning professor and Next City Vanguard alum, on the latest video on his YouTube channel, City Beautiful.

Most are in cities where urban population growth has stagnated, meaning these highways have fallen far short of transportation departments’ notoriously inflated traffic predictions (especially given how suburbanization hollowed out many of these East Coast cities). And political support is obviously crucial, too, especially if political leaders can be convinced that the property can be utilized in a more productive way that boosts local economic development.