Canada's new impaired driving laws come into force this week, and they change both what officers can ask for and what you can be charged with.

But the core message from police remains the same: if you're driving, don't drink or consume cannabis. And if you're going to do either, plan for another way home.

"The big message is, there's no change to the general public. Impaired driving, in all its forms, is illegal," said Sgt. Sean Harding, the head of the London police traffic management unit.

"It's against the law to drink and drive and it's against the law to consume drugs and drive. We need to make sure drivers have a plan to get home. If you plan on driving, if you plan on consuming, don't plan on driving."

The stricter impaired driving laws come into effect on Tuesday.

London police Sgt. Sean Harding, head of the traffic management unit. (Julianne Hazlewood/CBC News)

They allow officers to demand a breathalyzer test from any driver, even one who is not suspected of impaired driving. Until now, police had to have a reasonable suspicion of impaired driving if they wanted to demand a breathalyzer test.

Some lawyers think the new laws violate the Charter of Rights and Freedoms.

The new laws also increase the financial penalties for impaired driving and may introduce new "hybrid" charges that deal with drunk-and-stoned drivers.

"Are people getting the message? To say that people don't know the rules, you can't do that. The messaging is everywhere. There's just a core group of people that make poor choices," said Harding.

"We're still going to be out there, on the streets, looking for impaired drivers."

London police stop 20,000 vehicles annually and lay about 400 impaired driving charges.