Archaeologists are busy collecting artifacts and cultural items from the past along the path of the future South Mountain Freeway.
Crews are in the process of digging five-foot trenches to search beneath the surface of the 22-mile corridor. In other areas, archaeologists have found pottery, 19th-century shotgun shells, petroglyphs and other artifacts.
Evidence located important to the area's heritage will need to be managed according to federal and state historic preservation laws before freeway construction, according to ADOT.
The Arizona Department of Transportation has been studying sites that could be culturally significant for more than a decade.
"Protecting and preserving cultural resources is the law, but it's also the right and respectful thing to do," said Linda Davis, who leads ADOT's Historic Preservation Team.
South Mountain Freeway construction is expected to begin this summer. The freeway is expected to open by late 2019.