Speed camera vans are operating in hundreds of new locations all over the country from Monday morning.
The monitoring network is being expanded, with over 1,300 stretches of road now marked for enforcement.
Gardaí are increasing the number of areas where drivers' speed is being monitored after reviewing nearly a decade of data.
Over 1.5 million speeding tickets have been issued in the decade since the vans were first brought in.
The 903 new speed zones are being introduced on our roads.
They are being brought in to clamp down on dangerous driving as speed results in one-third of road deaths.
The new safety camera zones will be in place from 6.00am.
This means Gardaí have changed the locations where the vans usually are.
The new zones are being introduced in areas deemed high risk, while almost 600 zones are being phased out because of improved driver behaviour in these locations.
Gardaí insist speed vans are not a cash cow for the State, saying they save lives and cost twice as much as the income they generate.
They are also warning drivers that just because the speed zones in many areas have changed they will still be out in force nationwide targeting dangerous driving.
Since 2010, An Garda Síochána have used the safety cameras through 'GoSafe', which operates them on its behalf.
Gardaí say the primary purpose of the cameras is to reduce speed related collisions, lessen injuries and save lives.
Safety cameras operate in areas where there is a history of speed related collisions, known as speed enforcement zones, using a fleet of marked vehicles.
Road deaths have dropped from 415 in 2000 to 148 in 2019.
Gardaí say this shows "a dramatic reduction in terms of risk and a huge increase in terms of road safety."
All zones are available on the Garda website - or can be downloaded from GPS navigation providers such as Garmin, TomTom, Google Maps or Waze.