There's confidence roadside drug testing won't pick up prescription drugs.
Legislation giving police powers to do random saliva tests has passed its third and final reading in Parliament.
Police should be ready to use tests late this year.
Transport Minister Chris Bishop told Mike Hosking there will be two tests at the roadside.
He says it will be testing for cocaine, ecstasy, and marijuana.
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Mark the Week: The fuel excise debate is fantastically disappointing
02:47

Mike's Minute: Why didn't the Government drop the carbon auctions?
02:07

Wrapping the Week with Kate Hawkesby and Tim Wilson: Cancelled flights, parenting, calls from the Electoral Commission
11:09