Federal bureaucrats are raising concerns about distracted driving in semi-autonomous cars that don't require much input from the driver.

And at least one expert is anticipating that, as the so-called 'smart' cars get smarter, there will eventually be an increase in an unusual form of distracted driving: hanky-panky behind the wheel.

I am predicting that, once computers are doing the driving, there will be a lot more sex in cars. -

"I am predicting that, once computers are doing the driving, there will be a lot more sex in cars," said Barrie Kirk of the Canadian Automated Vehicles Centre of Excellence.

"That's one of several things people will do which will inhibit their ability to respond quickly when the computer says to the human, 'Take over."'

CBC's Aaron Saltzman took Tesla's new autopilot feature out for a spin. Media reports have flagged videos posted online showing Tesla drivers engaged in questionable practices, including reading a newspaper or brushing their teeth.

Federal officials, who have been tasked with building a regulatory framework to govern driverless cars, highlighted their concerns in briefing notes compiled for Transport Minister Marc Garneau soon after he took on the portfolio last fall.

"The issue of the attentive driver is ... problematic," said one note contained in a stream of emails about Tesla's so-called self-driving car.

"Drivers tend to overestimate the performance of automation and will naturally turn their focus away from the road when they turn on their auto-pilot," said the note, obtained by The Canadian Press under the Access to Information Act.

'Questionable practices' with Tesla autopilot

Indeed, the notes cite media reports of videos posted online showing Tesla drivers engaged in questionable practices, including reading a newspaper or brushing their teeth. Other videos show Tesla owners recording flaws in how the car's autopilot system reacts to changes in road markings.

Tesla did not respond to requests for an interview, but the company makes clear that its autopilot feature gives cars only partial autonomy in order to make the car significantly more safe than those driven by humans alone.

Transport Canada hadn't tested the Tesla, but had taken other semi-autonomous vehicles out for a spin, including the Mercedes C-Class and the Infiniti Q50, the documents show.

The New Mercedes C-Class Cabriolet is shown during the press day at the 86th International Motor Show in Geneva, Switzerland, Tuesday, March 1, 2016. Transport Canada hadn't tested the Tesla, but had taken other semi-autonomous vehicles out for a spin, including the Mercedes C-Class and the Infiniti Q50, the documents show. (Sandro Campardo/Keystone via Associated Press)

"It really needs to be emphasized that these vehicles are not truly self-driving," say officials, who predict that fully autonomous cars and trucks are "still a few years away."

Current Canada motor vehicle safety standards don't prohibit driverless vehicles on the country's roadways.

But last month's federal budget included money for Transport Canada to develop regulations around automated vehicle design.

Those regulations, at least initially, would require that the vehicles are equipped with a "failsafe mechanism that can respond to situations when the driver is not available," said the briefing notes.

Ontario also set out some regulations, including a requirement that an expert in autonomous vehicles be in the driver's seat and able to assume full control at a moment's notice.

But vehicles such as the Tesla don't fall under the province's autonomous vehicle pilot program, which hit the road in January, because its autopilot feature is already covered under regulations that govern the use of such technologies as self-parallel parking and brake assist.

Ensuring that a driver who may not have been paying attention to his or her surroundings can suddenly control a vehicle may be easier said than done, said Kirk.

"People will not be able to respond in time."

Federal officials also suggest autonomous vehicles be equipped with so-called "black box" data recorders, similar to devices found in larger aircraft.