The NRP stopped about 600 vehicles during R.I.D.E. programs in St. Catharines and Port Colborne.
Officers administered 26 roadside screening tests on Monday and four drivers found themselves in the warning range.
They each face a three-day licence suspension.
The officers also issued tickets for traffic related offences.
NRPS Buying Body Cameras for Officers
Police services board approved it for next year's budget, at a $1.2-million cost with US tariffs considered, after overwhelming community support
Arrests Made in Overdose Death
A 63-year old man was found dead in Niagara Falls motel last November
Truck Rammed into Harmony Jewellers
Pictures released by police... dramatic video online shows 5 criminals robbing store
NRP Monitoring Tariffs and Buying
Police services board approved buying guns from Canadian company, agreed Trump could change his mind anytime
St. Catharines Residents Charged in Huge Drug Bust
Police say Outlaw gang members involved from Toronto to Niagara and Nova Scotia
Body Found Near Lake in Wainfleet
An autopsy is scheduled, after passerby found the body yesterday morning near Lake Erie
Man Shot at Pearson Airport
Police say officers fired at him as he showed a gun while in Terminal 1 departures, the man died at hospital
NRP Looking for Man After Library Incident
Police called to the St. Catharines library