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.
Province Investing Against Invasive Species
The $2-million will help the Niagara region
Niagara Driver Charged with Drug Impairment
OPP say this happened on Highway 17, when a car was seen weaving all over the road
Welland Man Arrested for Child Porn
Police say they noticed child sexual abuse material shared on a social media page early this month
28 More Doctors Hired in Niagara
The region and Niagara Health coordinating new partnership to find even more doctors
Killed Police Officers Honoured by NRP
Police Chief praised Niagara members for standing at attention in 'pounding rain'
Niagara Wineries Shuttle Service Possible
The CUTRIC hopes the province supports helping people move among wineries
Canal Days Vendors Warned of Scams
The City of Port Colborne says criminals are sending fraud emails for payment
Niagara Falls Exploring Hub to Help Homeless
Former CAO Ken Todd has been meeting with community groups