Massachusetts officials say they are owed more than $15 million by out-of-state drivers who used the Massachusetts Turnpike without E-ZPass transponders.

Much of it will likely never be collected.

Of the 15 million in unpaid tolls– the state can only force payment of about $2.8 million. That is based on agreements with Maine and New Hampshire.

Drivers from those states can be blocked from renewing vehicle registrations unless they pay outstanding tolls.

A spokesman says the potential losses were anticipated when the new tolls system was put in place in 2016.