Gardaí stopped a driver in Carlow after he was caught speeding at 157km/h on the M9 motorway on Friday night.
The driver failed a breath test for drugs and the vehicle was seized for having no insurance as the motorist was disqualified.
He tested positive for having cocaine, opiates and cannabis in his system.
Following a search of the car, 2000 ecstasy tablets and a quarter kilo of cocaine with a combined value of around €40,000 were seized.
The driver, a man in his 20s, was arrested and taken to Carlow garda station where he was detained under Section 2 of the Criminal Justice (Drug Trafficking) Act 1996.
The man was questioned and later released pending a file to be sent to the DPP.
Gardaí have been clamping down on motorists as part of their May Bank Holiday road safety appeal.
People have been urged to reduce speed on the roads, with motorcyclists, in particular, urged to slow down and '‘ease off the throttle".
A motorcyclist in Co Wicklow was charged after he was detected travelling at 161km/h in an 80km/h zone.
The motorist was spotted while travelling on the N81 at Castleruddery Lower, Baltinglassin in a joint operation between Baltinglass Roads Policing Unit and regular units.
The offender will appear in Carlow District Court in relation to the offence.
In Dublin over the weekend, a motorcyclist was seen undertaking an unmarked garda car in a bus lane while travelling at more than 100km/h.
Dublin -This motorcyclist decided to use a 24hr bus lane to undertake an unmarked Garda vehicle at over 100kph! Most motorcyclists are responsible on the roads but some still fail to heed the warnings on the dangers of speeding. #Easeoffthethrottle #ArriveAlive pic.twitter.com/XR01Y4FLDz— An Garda Síochána (@GardaTraffic) May 4, 2019
Three people were arrested in the city on Friday evening after 10 intoxicant testing checkpoints were established by Gardaí.
One person was arrested on suspicion of drink-driving while two others were found to have drugs in their system.
Meanwhile, in Co Cork, two people were arrested on suspicion of drink driving.
Gardaí in Carrigaline made the arrests and seized two cars after they conducted a checkpoint in the area.