OTTAWA -- The federal government says new pilot-project results suggest roadside testing devices can be successfully used to detect drug-impaired driving -- another milestone on the road to legalizing recreational marijuana use.

Police officers from seven jurisdictions across Canada collected over 1,140 saliva samples using two kinds of devices between mid-December and early March.

Officers reported that the screening devices were easy to use in various weather, temperature and lighting conditions, Public Safety Canada said Tuesday in releasing the findings.

"The results from this pilot project indicate that with the proper training and standard operating procedures, these devices are a useful additional tool for Canadian law enforcement to better detect individuals who drive under the influence of drugs."

The Liberal government is moving to legalize recreational marijuana use, saying it will help keep the drug out of the hands of young people while denying profits to criminal organizations.

Under recently introduced legislation, police would be able to demand a saliva sample from a driver if they reasonably suspected the person had drugs in their body.

Should the saliva test lead police to believe an offence has been committed, they could order an examination by an evaluating officer or the taking of a blood sample.

Portable screening devices can detect the recent presence of several drugs, including THC -- the active ingredient in cannabis -- cocaine, methamphetamines, opioids, benzodiazepines and amphetamines.

During the tests, saliva samples were collected through random stops and roadblocks, with 80 per cent taken from drivers and 20 per cent from passengers. About 15 per cent of the tests registered a positive drug reading, Public Safety said.

Testing occurred in clear, snowy and rainy conditions, at all times of day, with temperatures ranging from -50 C to 26 C.

The report makes several recommendations concerning standard operation of the devices as well as core training for police forces.

Mario Harel, president of the Canadian Association of Chiefs of Police, said his organization supports the pilot-project findings, adding the devices are a necessary element of the overall strategy to detect drug-impaired drivers.

The Canadian Automobile Association said while it was pleased to see the government testing drug screening devices, the real question is how police will pay for these and other tools.

The best way to prevent drug-impaired driving is through public education, and "the association hopes the government comes to the table with funds for these tools and to educate the public on the dangers of marijuana-impaired driving," said association spokesman Jeff Walker.

Public Safety Minister Ralph Goodale said recently that he and Justice Minister Jody Wilson-Raybould would have an ongoing conversation with provincial and territorial counterparts about the necessary resources.