Complex sentence: During the interstate highway system's late 1950s and early 1960s building boom, public parks had been viewed as desirable to build through because doing so didn't require the federal government to use the power of eminent domain.
Split into simpler sentences: During the interstate highway system's late 1950s and early 1960s building boom, public parks had been viewed as a desirable path. Building through them didn't require the federal government to use the power of eminent domain.