Figures from gardaí show that 693 vehicles have been detected travelling in excess of the speed limit during the first few hours of National Slow Down Day.
Gardaí began the 24-hour crackdown on speeding at 7am.
The operation, which is supported by the Road Safety Authority, will run until 7am tomorrow morning.
So far, the speed of a total of 87,350 vehicles were checked. One vehicle was clocked travelling at 202km/h on the M50 in Dublin.
Gardaí say the levels of speed have increased on the roads during the pandemic, despite reduced volumes of traffic.
National Slow Down Day— An Garda Síochána (@GardaTraffic) May 22, 2020
Motorist detected travelling at 202km on the M50 this morning now faces a hefty fine and possible disqualification from driving. Excessive speed contributes to serious injuries and fatalities. #SlowDownSaveLives pic.twitter.com/bjmiZqgydS
Among the examples in recent weeks, gardaí recorded drivers travelling at 119km/h in a 60k/h zone on the Old Airport Road, Cloghran in Dublin.
They also detected a driver travelling at 129km/h in a 60km zone in Kenagh in Co Longford and a driver travelling 156km/h in a 100km zone in Inagh in Clare.
One vehicle was detected travelling at 85km/h in a 50km/h zone in Donegal.
To date this year, 57 people have been killed on Irish roads, an increase of six on same period last year.
Pedestrians account for 30% of all fatalities this year.
The operation will involve high visibility enforcement in 1,322 speed enforcement zones.
Chief Superintendent of the Roads Policing Bureau Paul Cleary said that the operation is all about making the roads and communities safer.
"Despite the reductions in traffic associated with Covid-19 we have continued to see a small percentage of motorists who travel at excessively high speeds both in urban and rural areas," he said.
"Whilst the vast majority of drivers drive safely within the speed limits, and it is most welcome, there still remain those who continue to drive at excessive speeds. We will maintain our focus on non-compliant drivers as they pose a risk to themselves and other road users," he added.
181 vehicles detected travelling in excess of the applicable speed limit on National Slow Down Day so far— An Garda Síochána (@GardaTraffic) May 22, 2020
124km/h in a 80km/h Zone - M50 Kilmore Big Dublin17 Dublin
121km/h in a 100km/h Zone - N11 Kilmurry North Kilmacanoge Wicklow#slowdownsavelives pic.twitter.com/TP0h8RKAjN
Interim CEO of the Road Safety Authority John Caulfield said by slowing down a driver will have more time to react.
He said: "If a pedestrian or cyclist is hit at 60km/h they only have a 10% chance of survival, but if hit at 30km/h they have a 90% chance of surviving.
"By slowing down a driver will have more time and space to react to any potential hazard on the road. It also increases the likelihood of surviving a crash."
Gardaí say they will be using media channels today to remind motorists of the potential impact on families and communities of speeding.
Pedestrians urged to take care while social distancing
A garda superintendent has appealed to pedestrians to be aware of the rules of the road while they adhere to social distancing when they are out walking.
Speaking on RTÉ's News at One, Supt Eddie Golden from the Roads Policing Unit said people are taking risks when they are out walking by straying on to the road, to maintain a social distance from others, but are not aware of oncoming vehicles.
He urged people to "go back to basics" and take more care when walking.
"The rules of the road apply to all road users," he said. "We would never have walked out on to the road without looking left or right.
"I'm appealing to particularly pedestrians to be aware of that, and also from wearing headphones when they're walking around.
"That's another areas where we're finding people are being distracted, and stepping out on the road and we have seen instances of this all over the country."
Additional reporting Sinéad Hussey