Motorists are being warned not to drink or take drugs while driving.
Two people were killed over the May bank holiday last year, and the Road Safety Authority is urging people to slow down over the coming days.
Gardaí can now test drivers for drugs, similar to breath testing.
Communications Manager with the RSA, Brian Farrell said: "What the Gardai are doing is they are going to be testing people for illegal drugs like cannabis, cocaine, and heroin.
"It will also pick up drugs on the perscription side of things, so people who are taking drugs for medicinal purposes," he said.