Thurrock Council has long opposed plans for the Lower Thames Crossing and recently made it clear to Highways England that proposed Environmental Impact Assessments did not go far enough.
Highways England wrote to the council on 4 June agreeing to carry out a standalone Health Impact Assessment.
Cllr Mark Coxshall, portfolio holder for regeneration, said: "We are glad that Highways England have listened to the voices of residents and have agreed to properly examine the health impacts of the Lower Thames Crossing.
"A full Health Impact Assessment will ensure Highways England look in detail at the scale of the crossing and the impact it will have on residents. They must also demonstrate how the scheme will make residents lives' better."
Chair of the Lower Thames Crossing Task Force, Cllr Peter Smith, said: "This is a very real victory for the Lower Thames Crossing Task Force.
"Through joint work with other authorities' directors of public health we have secured this important health assessment. We will continue to engage with Highways England to ensure that residents’ views are fully represented."