A new book: "28 Days: What Your Cycle Reveals about Your Love Life, Moods and Potential", by US health journalist Gabrielle Lichterman, purports to explain to women how to tailor their days according to their timing in the body's hormonal cycle.
And it could explain why women have sudden unexplained moments of road rage or drive much faster than their usually cautious gait, why they have accidents while in a seemingly easy parking situation, and why they'll suddenly get a yen for a particular car, and want to buy it immediately, rather than thinking the whole thing over.
Or maybe they'll display unexpected passion on the drive home from dinner and want to pull over into a quiet spot - even though they're only two or three km away from home!
The book is based on what author Gabrielle Lichterman terms "hormonology", which she describes as " the science of predicting your day and planning your life according to your hormone cycle."
On her website (http://www.28days-thebook.com) she says:
"I began developing hormonology in 1999.
"It all started while I was doing research for a health article I was writing.
"I had come across a study that found on high oestrogen days in a woman's cycle she's more attracted to rugged, masculine-looking men, and on low oestrogen days in a woman's cycle she's more attracted to feminine-looking men.
"This was surprising, since up till that point the most women heard about their hormones was that they caused a cranky PMS mood. The idea that they could also affect the kind of guy you're attracted to was revolutionary.
"Curious about the other surprising ways hormones affect women, and men for that matter, I went on a search for more hormone studies.
"In the span of a few short months I found dozens of other studies showing even more surprising ways hormones affect women and men.
"And what this research revealed was that hormones affect us in virtually every way - including our mood, brain skills, relationship, libido, money, career, energy, diet, health and more.
"I spent the next four years continuing my hormone research, scouring endocrinology newsletters, medical journals and books, and conducting interviews with many of the world's top hormone scientists."
The book is laid out like a daily horoscope, and has an easy-reading and often humorous style to make its scientific evidence easier to take in.
"Oestrogen, testosterone, and progesterone - three of a woman's most influential hormones - have a powerful impact on virtually every aspect of a woman's day, including her mood, brain skills, relationships, libido, career, diet, energy, and health," adds Lichterman in the book.
"Armed with this information, women can capitalise on each day's strengths, minimise weaknesses, and find out the perfect day to schedule important events."
Hints for the road
Day 1 - the start of your period.
This is a time for caution. Oestrogen and testosterone levels are extremely low. You have a low attention span and can't find stuff you don't normally lose - such as your car keys.
The good news, though, is that if you have to go into town you'll be able to slot the car into the smallest parking space as you find it easy to judge gaps and distances.
Take it easy, keep your following distance, and ignore all the pathetic idiots on the road around you. Slide a Norah Jones CD into your car stereo.
More oestrogen and testosterone are starting to pump into your brain, and as a result there aren't QUITE as many idiots on the roads today. But still be careful!
Hey, where did that turbo power come from? The oestrogen and testosterone levels are still rising, and suddenly everything is starting to get clearer - you're driving in the fast lane.
Remember that talk you had with hubby about taking advanced driving lessons? Now would be a great time to do it! Kyalami here I come.
Hey, let's go down and have a look at that zooty little hatchback you've been eyeing? Maybe you should trot down to your local car dealership and have a test drive - even treat yourself and buy it!.
For the next five days you're going to be feeling confident about your finances, says Lichterman, but not overly confident.
"You're thinking and speaking logically, since you're ruled by your left brain during this period," she says.
"If you wait till Days 11 through 13, you'll feel overconfident about your finances and will be more easily swayed by an exuberant salesperson.
"And if you wait till days 14 through 28, you'll be feeling less confident about your finances, more suspicious of the salesperson, and you're more apt to end up with a car that doesn't suit your needs."
Wow, you're feeling SO sexy" Yes, it's oestrogen that's doing it, and you want to sing to the world and flash your legs at the cute 4x4 driver peering into your car from his lofty cab alongside in the traffic. You're tapping the steering wheel in tune to the music blaring out of your radio.
This is the time of the month your partner enjoys the most.
And there's another week of this heavenly feeling. Why don't the two of you take a drive into the country - maybe with an overnight bag just in case?
Days 10 to 13
Now you're really cooking! Your mind is clear, your co-ordination is superb, and your reactions are as fast as a Michael Schumacher gearchange. You can drive better than anyone else on the road, and you're ready to dice with anyone who wants to - or even those who don't. Time to take hubby's Beemer to work and let him drive the family hack.
Lichterman says. "With oestrogen and testosterone peaking, you're thinking faster on your feet, absorbing information more quickly, and your hand-eye co-ordination is at its best.
"You're feeling super confident and bold, ready for adventure."
It's the middle of your cycle, and you're ovulating, and suddenly everything feels different. You're still looking at cars, but this time you're more interested in baby seats than Recaros.
You think that ad. with the dog chewing in the back of the car in tune with his teen driver is SO cool, and you find yourself enjoying the cartoons on morning TV, especially the ones which feature big cuddly characters - although maybe Noddy and that irritating hooter is pushing it a bit far. Maybe.
But there's more - you're hungry as hell. And it's all the stuff you shouldn't eat that you fancy, such as potato crisps, salted peanuts, and a fat MacDonalds with all the extras!
Take control, girl, or you'll pay on your thighs.
Days 15 - 17
"Oh, oh..." as Lichterman writes, this is "a dress rehearsal for the real thing " - PMS.
The problem is that oestrogen and testosterone levels are falling, while progesterone is on the way up, and it's sapping your both your energy and patience levels. You feel irritable, and may find your moods swing.
Better drive VERY carefully as now's the time you're likely to slam on the brakes if someone gets too close to your taillights, or get involved in a screaming match at a robot because the woman next to you hasn't buckled-up the child in the front seat. Even if you're right, it's not the best way to get a positive result!
Days 18 - 23
The calm before the storm. It's now progesterone that's the driving factor in your hormone race. Known as the "calming hormone", it's been shown to be eight times more powerful than a common barbiturate, so now's the time to take the kids for a long drive in the country.
You'll even be placid enough to teach your teenage daughter to drive!
Days 23 - 28
This is the time you're been dreading - the start of real PMS. All your hormone levels have dropped, and you'll battle to find your way to the mall, let alone to that appointment at the other end of town where you don't usually go.
"All three of your hormones are falling, causing more intense periodic moodiness, irritability, and temper flares," says Lichterman.
"When your oestrogen falls, your serotonin falls and when serotonin falls a chemical called noradrenaline rises. Noradrenaline is responsible for that quick-to-anger feeling, which is why you're more likely to feel irritated."
Don't put any sad CDs into your car stereo today - you could end up getting more stares than you bargained for as you suddenly burst into tears for no apparent reason while driving to work.
Your hormone levels are at their lowest, and you're feeling really miserable.
Take a box of tissues in the car with you.
But take heart - just a short few hours, and your period will start. Your'll feel a lot better.
The concept and structure for this article was suggested by a piece by Carol Traeger, writing on The Car Connection website.