Every day when Andrea Burnett drives by a white wooden cross on Highway 207 near Lawrencetown Beach, she thinks of her husband Mark.

He died there in July 2013, just a few kilometres from their home in Lake Echo, killed by 21-year-old Kyla MacLellan, who was driving drunk.

"I tell him good morning or if I'm coming home, I say good night," she said. "On our anniversary, last Thursday, I wished him a happy anniversary and told him I loved him."

Andrea Burnett's husband, Mark Burnett, was killed by a 21-year-old female drunk driver in July 2013. (Jack Julian/CBC)

It's time, she says, to discard the old-fashioned notion that impaired drivers are only older men.

"Without meaning to, we're stereotyping," she said.

Someone who has given plenty of thought to what kind of person drinks and drives is Const. John McLeod, a Halifax Regional Police officer who works in a windowless office in a former elementary school, now a police training facility in Dartmouth.

Once a week, McLeod sits down at his computer and pulls up a list of everyone who's been charged with impaired driving, then he plugs those numbers into a spreadsheet.

Burnett was killed by a drunk driver on Highway 207 near Lawrencetown Beach in July 2013. (Courtesy of Andrea Burnett)

For the past three years, he's been building a profile of people who drink and drive in Halifax.

"If you understand the nature of the information, then hopefully you have a way to go out and counter that. Information is power," said McLeod.

Though he won't go into details, he says his interest in impaired drivers isn't only professional.

"My family, like many others in Canada, has been touched personally by impaired drivers. So when certain things touch close to home and you're affected by that, it motivates you to change it," said McLeod.

Unprecedented numbers

According to McLeod, women make up 24 per cent of impaired drivers charges in Halifax so far this year, the highest proportion he's seen so far.

Women became responsible for a greater percentage of drunk driving charges in Halifax between 2012 and Oct. 31, 2015. (CBC)

That's consistent with both national and provincial trends that show women are accounting for a bigger percentage of drunk driving charges.

According to Statistics Canada, the number of impaired driving charges in Nova Scotia is falling over time. Between 1998 and 2014, the overall number of charges per year dropped from 2,284 to 1,822, a decrease of 20 per cent.

But while fewer men are being charged, the number of women is increasing.

Charges against men dropped from 2,061 in 1998 to 1,507 in 2014, a decrease of 27 per cent. During the same time period, the number of charges against women increased from 223 to 315, a jump of 41 per cent.

Causes of trend unclear

McLeod says he doesn't know what is causing more women to drive drunk.

"There doesn't seem to be a great difference in why they're drinking or when or how," he said.

But one of the reasons could be physiology.

Erica Brooks studies drinking trends among women and girls with the Nova Scotia Health Authority's addictions and mental health program.

She says differences in body fat and metabolism mean if a woman and a man of equal size drink the same amount of alcohol, the woman will become impaired faster.

Brooks says women are more vulnerable to the short-term impacts of alcohol.

"Injury, DUIs, unplanned pregnancies, unprotected sex, those kind of acute risks because they do actually become impaired quicker than men," she said.

The number of women charged with drunk driving has increased by more than 41 per cent between 1998 and 2014 in Nova Scotia. (CBC)

Brooks also says women take longer to eliminate alcohol from their bodies and may become unintentionally impaired while drinking socially.

"A woman may go out and have a glass of wine with dinner, not realizing the time they might need to metabolize that alcohol," she said. "[I'm] not saying that they are severely intoxicated when they get caught, but their [blood alcohol content] may be over the limit."

Brooks says women in Nova Scotia now consume alcohol at roughly the same rate as men.

Shifts in how women drink

She believes the rise in women's alcohol consumption patterns is influenced by marketing.

"We see low-calorie alcohol, we see flavoured alcohols and we now see a lot of flavoured beer, so those shifts have influenced women drinking over the past couple decades," said Brooks.

She also believes the placement of liquor stores beside many grocery stores has made alcohol buying more convenient.

"We know it is significant because 80 per cent of grocery store consumers are women, so the access and availability of alcohol is much easier now. So when they go get groceries, they can simply just walk into the liquor store and grab their bottle of wine," said Brooks.

McLeod doesn't think there's any way to focus police enforcement efforts on female impaired drivers.

He believes beginning anti-drunk driving education at a young age and considering both boys and girls in program design will help in the long run.