The speed limit on a 12 kilometre section of Heathcote Road will be cut from 100km/h to 90km/h from next Monday, April 15.
Roads and Maritime Services is making the change between Lucas Heights and Voyager Point following the head-on crash on January 31, which claimed the lives of police officer Timothy Proctor and another driver.
Constable Proctor died in hospital three days after the accident, and the driver of the second car, a woman, 65, whose name was not released, died on March 7.
The crash occurred about one kilometre west of the intersection of Heathcote Road and New Illawarra Road, Lucas Heights.
RMS executive director Sydney John Hardwick said a speed zone review was carried out following the accident and requests from the community.
"Roads and Maritime will be installing a 90 km/h speed limit along a 12 kilometre length of Heathcote Road to provide safer journeys for all motorists," he said.
"The speed limit will be reduced from 100 km/h to 90 km/h between 250 metres east of The Avenue, and 150 metres west of New Illawarra Road.
"The remaining speed limits along Heathcote Road will remain the same."
Mr Hardwick said the change would come into effect on Monday, April 15, weather permitting.
"The speed limit changes are expected to provide a consistent speed limit and bring significant road safety benefits to the residents and all road users in this area," Mr Hardwick said.
"The changes to the speed limits were assessed on a number of factors including crash history, road geometry, road environment and traffic volumes.
"Electronic message signs will be in place to advise motorists of the lowered speed limit."
Mr Hardwick said RMS was continuing to plan for the installation of audio tactile marking along Heathcote Road between MacArthur Drive, Holsworthy, and Princes Highway, Engadine.
"Roads and Maritime is also continuing to investigate options for road widening along this busy road corridor, which will include the installation of central median barriers," he said.
"The community will be kept informed as plans progress and motorists are reminded to drive to the speed limit at all times for the safety of all road users."
