Thank you for the additional information.

It sounds as though had just the roadside suspension, as he must have failed the roadside test and there was insufficient evidence to try to charge him criminally.

The police are entitled to pull over any vehicle in order to check registration, look for signs of Impairment, or check the mechanical fitness of the vehicle. As long as this is their purpose in pulling over a vehicle, they do not need to have any actual suspicion or other grounds to stop a vehicle and can do so at random. So it sounds here that they wanted to check registration. So I cannot offer him much hope unfortunately that he will succeed on appeal on the basis they had no legal right to pull him over.

They would have a legal right to request him to take the roadside great test if they had some reasonable suspicion that he had any alcohol in his body. A smell of alcohol on his breath would be sufficient usually to give that suspicion and authority to demand the breath test.

This is an issue that has been addressed by the Supreme Court of Canada. They have acknowledged that this type of arbitrary stop is an infringement on personal rights, but have said that it is justifiable in our society given the need to police the roads and ensure safety for all the public, and so the minor infringement is outweighed by the public interest overall. So an officer can pull over any motorist as they see fit, at any time, if they are validly checking one of the three items of impairment, registration, mechanical fitness. You are correct that sometimes officers late at night on a slow shift will just randomly put in licence plates that they encounter or pull over vehicles.

It can be an abuse of power if an officer pulls over a vehicle with no cause or suspicion to do so, and indicates that it was not for one of these three grounds. Usually officers will just robotically say that this is the reason they pulled over a vehicle, one of the three grounds. Or they had some reasonable suspicion of an offence or actually saw an offence, such as running a red light or erratic driving. But if their evidence was that they pulled over a vehicle as they had some concern that is not connected to the three grounds, and then that concern is found to be without foundation by a court, then the traffic stop is illegal, and possibly any evidence gained through that stop can be excluded.

So if an officer were to stop a car because the driver was black, for example, saying he thought it odd that a young black man was driving an expensive car, then this has nothing to do with the three grounds, and there is no cause to think any offence has been committed and none was observed. A person's race does not give any legal grounds for suspicion of an offence that would justify pulling over a vehicle. So if an officer had been honest in their notes or testimony in such a situation as to why they stopped the vehicle, likely an impaired driving charge in such a situation would be dismissed because the stop was illegal.

The roadside devices do not indicate an exact breath reading, just a pass or fail indication. That is why drivers are taken to a police detachment for a different breath test that can result in a criminal charge for exceeding .08. The roadside devices are not accepted under the criminal code as having the accuracy to give an exact number. But they are accepted for the type of roadside test and suspension at issue with your son.

He has every legal right to fight this matter. His choosing to do so cannot increase the penalty, so in that way he has nothing to lose.

What is viewed as minor by the Supreme Court is the detention of a person for a few minutes while the vehicle is stopped by police so that they can make the checks that are allowed by law. That is seen as a minor price to pay to try to keep roads safe. The court (and I) did not mean that the results of that detention are minor. Those results could range from being very minimal such as the driver being told to proceed on their way, to being very serious, as routine traffic stops can result in a person spending years in jail, such as where drugs or weapons are found in a vehicle. But the legal test to pull a vehicle over is the same, no matter what consequences might come to an accused person as a result of that happening. I did not mean to minimize what has happened to you and your son. The results here are more serious than a mere speeding ticket or so on, but that does not change the law regarding whether police had the right to pull him over or not.

The officer does not need to prove that he had suspicion that the vehicle was stolen, or that he thought the person was driving erratically, or so on. It is enough if the officer testifies that he pulled the vehicle over to check registration. Here that is what I would expect the officer would say, as he was curious that the driver did not appear to match the age/gender of the registered owner. That would not be enough to give anyone a reasonable suspicion that the car is stolen, but no such suspicion is required in order to legally pull over the vehicle.