Here's why this former CIA spy stops at every yellow light

• Insider recently obtained an advance copy of "Life Undercover: Coming of Age in the CIA," a new book by former clandestine services officer Amaryllis Fox, which is out Tuesday.
• In an interview, Fox talked more about why she wrote the book, her training, her experiences in the field, and even some of the weird habits that won't go away.
• Among habits like keeping her back to the wall at restaurants or watching entrances and exits is stopping at every yellow light.
• Visit Business Insider's homepage for more stories.

After spending years in the CIA fighting to prevent nuclear terrorism and other catastrophes, some old habits just will not go away for ex-spy Amaryllis Fox.

"I try to kind of shed those instincts," Fox, a former CIA clandestine services officer and author of the new book "Life Undercover: Coming of Age in the CIA," recently told Insider. "But I think they really are in your subconscious for a long time, at least some of them."

CIA spies learn to master skills regular people do not, and they stick with you.

They learn to be so immersed in their cover that they can pass a polygraph test, to spot the perfect meeting site that is just isolated enough to avoid the eyes and ears of the enemy but also can be explained if discovered, and to handle tails - surveillants that could jeopardize an entire operation.

"When I walk around cities, I'll notice what would be a good signal site or what would be a good brush-past site," Fox told Insider, referring to sites where a marking indicating a message could be left or where discreet exchanges could be made.

On two different occasions in civilian life, she said, she spotted what she suspects were signal markings, usually chalk or even antacid tablets for plausible deniability, left by other officers in places she thought would make good locations.

"Those habits of kind of noticing good operational sites are still with me," she said. "I think that this is just kind of a habit that will be with me for the rest of my life."

Fox also mentioned that she feels more comfortable with her back to the wall in restaurants and that she tends to take note of entrances and exits wherever she goes.

But there is one old habit, she said, that drives her husband a little bit crazy - stopping at every yellow light when she drives.

What's the deal with the yellow lights?

"When you do counter-surveillance training, one of the things that you are taught is not to piss off your surveillant and make them think you are trying to lose them," Fox explained.

"So, if the light turns [yellow]," she said, "you stop so that they don't get the sense you shot through it with an attempt to lose them."

Handling a tail is not like what most people have read or watched in spy thrillers.

"The way these operations are portrayed on TV and in movies, where someone jumps on a train and loses the surveillant or they jump between rooftops with their weapon drawn, nothing could be further from the truth and the reality of deployment," she said.

"That would draw a huge amount of attention to the officer even if they got away that one time. Their cover is then blown," Fox told Insider. "A lot of the training involves being very non-alerting, pretty much just very boring so that we aren't drawing attention to ourselves."

She added that most of what is seen in spy movies, like downplaying human intelligence in favor of hyping the paramilitary aspect or inaccurately portraying female characters and the meaningful contributions they make to this type of work, is wildly off the mark.

Commenting on her pride in seeing four women in the top positions at the CIA, she said, "I hope that the screen portrayals that we see going forward have a more substantive reflection of women's contributions to national security."

"They are really so important," she added.

Fox spent her time in the CIA preventing weapons of mass destruction from falling into the wrong hands, working behind the scenes to address terrifying threats she says would "overwhelm" the average American if they knew.

Her new book detailing some of her training and her experiences and offering a peak behind the curtain of CIA operations is out Tuesday.