State transportation officials have installed electronic toll collection equipment on the northbound lanes of the Tobin Bridge, but drivers will not see an increase in overall fees once the system is activated this fall.

Currently, inbound drivers pay a $2.50 toll as they cross into Boston. When the new equipment is in operation, drivers will pay $1.25 in each direction, Department of Transportation spokeswoman Jacque Goddard wrote in an e-mail this week.

“Starting with public meetings in 2013, MassDOT officials have stated that the Tobin Bridge would have a toll in one direction only as long as cash payments were being taken but then would return to having tolls in each direction after All Electronic Tolling is activated statewide,’’ she wrote.