The Boston Transportation Planning Review (BTPR), published in 1972, was a pioneering program designed to analyze and redesign metropolitan Boston's entire transit and highway system during the 1970s. Recognized by the U.S. Department of Transportation as the prototype for similar reevaluations in major American cities, it significantly shaped the region's infrastructure. Directed by Alan Altshuler, the BTPR introduced several major elements, including conceptual designs for the rerouted Orange Line and expanded Red Line services. Crucially, the review imposed a moratorium on expressway construction inside Route 128 and first proposed depressing the Central Artery, a concept that eventually led to the massive Big Dig project. The program also championed advanced technologies for environmental impact analysis and involved extensive public consultation under Governor Francis W. Sargent, ensuring a comprehensive and community-informed approach to urban planning.