As of midnight, police no longer need a reason to ask drivers they think could be drunk or high for a breath sample.

The overnight change in Canadian law that some critics are calling unconstitutional also ensures those caught behind the wheel while impaired will face steeper fines and a higher risk of jail time.

Read details of the updated impaired driving law from the federal Department of Justice

In the past, roadside checks meant police might smell a driver's breath or ask them questions, because they were required to have a reasonable suspicion to demand a sample.

But as of Dec. 18, "when police pull you over, they no longer have to have a reasonable suspicion," criminal lawyer Paul Doroshenko said.

The lawyer with Acumen Law Corporation who’s handled thousands of impairment cases is among those who say the law is unconstitutional.

In addition to having a criminal record, those who refuse to submit to a breathalyzer will now face harsher penalties. Refusing a first time means a $2,000 fine, while a driver who refuses a second time could face a minimum of a month behind bars.

A third refusal can mean 120 days in jail.

"The question is, will there be any criteria that police start using themselves?" Doroshenko said.

Vancouver police say demanding a test will continue to be up to officers' discretion and "based on the circumstances of the stop."

Among the issues, Doroshenko said, is those who can't provide a sample, such as elderly drivers, or those who don’t drink, and believe they shouldn’t have to provide a sample when asked.

"Until it's struck down, I wouldn't want to be the individual who's the test case," he said.

But with an average 68 people dying each year in B.C. in crashes involving impairment, according to ICBC, both advocates and law enforcement say higher penalties and more checks are one more tool to take dangerous drivers off the street, and to make others think twice.

"Every single death or injury due to impaired driving was something that didn't have to happen," said MADD Canada's Carolyn Swinson.

Under the new law, she says, more people can be stopped and more can be tested.

Swinson, who lost her son to a drunk driver, has spent the last 25 years pushing for change.

"If you talk to people and you ask them why they did it they'll tell you they thought they were going to get away with it," she said.

With a report from CTV Vancouver's David Molko