Thousands of homeowners living close to the M6 Toll road are still waiting for compensation - nearly four years after it opened.
The Highways Agency says it has taken on extra staff to settle claims
More than 11,000 claims have been submitted, which was far more than were expected, but 5,000 have yet to be settled, the BBC has learned.
The Highways Agency is using a noise map as one of the methods of deciding the levels of compensation.
It said it had taken on extra staff to address all claims within six months.
Steve Hinton, the chartered surveyor helping many of the claimants, described the situation as "almost comical".
"The government, with the best of intentions, keeps introducing so-called improvements to the system, but all it does is delay matters considerably," he said.
The Highways Agency said in a statement: "We are dealing with every claim professionally and as quickly as we can.
"We have now taken on additional staff and we aim to address all of the remaining claims within six months."
The level of compensation has been deemed to be "commercially confidential" because the M6 Toll is a private road, but it is understood that when everything has been settled the final bill is expected to be up to £40m.