An $8 million noise wall completed last year on the Stanley Avenue-Stephensons Road freeway section was fitted to a 68 dB(A) noise standard, five decibels louder than the standard for EastLink sound barriers. In a survey last year, about 200 residents near the section complained of increased road noise after the wall was installed. The outcry prompted VicRoads to start noise testing, which will end after the completion of freeway roadworks.

Resident Peter Smith said the five-decibel gap in standards was bigger than it sounded, a 10-decibel jump being equal to 10 times the noise intensity. "This shouldn't be about the numbers game. It's the fact that a significant majority of residents think [the noise is] worse or no better.''

Mr Smith fears the noise will increase when normal speed limits resume after the roadworks, which will widen the freeway from six to eight lanes.

VicRoads acting regional director Andrew Williams declined to comment on the discrepancy between Monash Freeway and EastLink noise standards.