The changes in the design of the northern Taconic also reflect higher speeds that mid-century automobiles were capable of, and improvements in construction technology. The track-equipped steam shovels that broke ground for the first section in Putnam County in 1931 were the most advanced excavators of the time. Over the next decade, the cost of moving a cubic yard dropped to almost half of what it had been in the early 1920s. Later in the parkway's development, engineers began using aerial photographs to plan the route.