Mandatory drug testing of drivers involved in a road crash will begin on Friday.
Currently, gardaí carry out mandatory alcohol testing of drivers involved in serious collisions, though they had a discretionary power to conduct test for drugs.
The Department of Transport said the additional mandatory drug test was due to research and evidence indicating that drug driving is increasing on our roads.
It said the change is intended to discourage dangerous driving behaviour and ensure that all those who drive under the influence and are involved in a serious collision are detected.
The roadside drug test usually takes eight minutes to show results, although the new law sets a maximum waiting period of 30 minutes after a driver has supplied an oral fluid sample in case of a faulty test or another motorist in need of urgent assistance.
Minister of State for Transport Jack Chambers, who signed the changes into law, said: "Driving under the influence is one of the four main causes of road fatalities and it is simply unacceptable.
"Ensuring that enforcement by An Garda Síochána is underpinned by robust road traffic legislation is a priority for me and my Department. Government is committed to doing all it can to reverse the really alarming trends we have seen in recent times, where fatalities have been rising year-on-year."
The Department of Transport said it approved the Medical Bureau of Road Safety to purchase an additional 10,000 'Drugwipe' test kits to be used by gardaí this year.
In addition to the introduction of mandatory drug testing, Mr Chambers also signed into law new legislation for safer default speed limits on urban, national secondary and rural, local roads, as well as introducing other road safety measures which will be implemented in stages.
