At a preventive checkpoint, can officers subject a driver to a drug detection test?

It is mandatory to undergo breathalyser and drug tests. Refusal to undergo such tests constitutes a criminal offence of serious disobedience. The Authority's agents responsible for traffic surveillance may subject the following to such tests: - Any road user or vehicle driver directly involved as a possible party responsible for a traffic accident. - Those who drive any vehicle with obvious symptoms, manifestations that indicate or facts that reasonably allow the presumption that they are doing so under the influence of alcoholic beverages. - Drivers who are reported for committing any of the traffic regulation infractions. - Those who, while driving a vehicle, are required to do so by the Authority or its agents within the preventive alcohol checkpoint programmes ordered by said Authority.