The first weekday rush-hour of all-electronic tolling on the Massachusetts Turnpike and in the Boston Harbor tunnels is in the books — and there were no major delays.

The switch from tolls collected by workers in booths to a system using gantries above roadways began late Friday night.

State transportation officials had warned that heavy traffic was possible as crews tear down the existing tollbooth plazas and reroute vehicles around the demolition work. They urged car commuters to avoid the highway at peak times, or to seek alternative modes during the construction.

Department of Transportation officials said that the number of drivers on the Pike was down by about 6 to 10 percent Monday morning, compared to normal.

At a press conference Monday, State Highway Administrator Tom Tinlin said he was relieved that traffic was lighter than normal.

"There's no way around it, this morning went really well," Tinlin said. "And I do believe that the credit goes to months of planning, coordination and execution but the real credit goes to the traveling public."

The department says it will continue to monitor traffic conditions for Monday afternoon's commute.

Transportation officials say nearly half of the tollbooths along the Pike have been taken down so far, but they're continuing to urge drivers to leave extra time and avoid the highway at peak times if possible.

Photos of toll both demolitions on the Mass Pike:

Contractors tear down one of the Allston toll booth houses along the Mass Pike. (Jesse Costa/WBUR)