The incidents all involve two or three suspects. It's possible all three robberies are related.
The first robbery took place on Saturday at Southfield and Schoolcraft roads.
Monday afternoon, a crew working near Livernois and McNichols was robbed at gunpoint. Then a few hours later, another incident happened near the Lodge Freeway and Seven Mile Road.
No one has been injured in any of the robbings.
DTE Energy is offering a $2,500 reward to help catch the suspects.
If you have any information, call Detroit police.