Drive to Survive.

it may be a tad ‘late’ for my American readers who may have already enjoyed an annual vacation, perhaps taken in the family car?

But in case it is not, and also for any Aussie readers, i’d like to share a little of something i have been concerned about recently.

We all know that driving can be hazardous to your and other people’s health with around 2000 out of some 20 million Aussies dieing on our roads every single year and over 40,000 in the US by reason of a much larger population (and worse drivers) 😉

What you may not yet realise is that there could be a cause you least expect that adds significantly to the loss of life on long vehicle trips – especially when more than one person is in a car – like say, in a family.

it’s what you are breathing!!!

If you have to drive for a period in excess of three hours straight with four adults in a car and have all windows wound up and the A/C either on ‘recirculate’ or ‘off’ your natural breathing may simultaneously reduce the available oxygen going to your brain and increase the Carbon Dioxide in your blood so that you become drowsy – and in some cases fall unconscious!

Definitely not something anyone on the road wants a driver to do – especially at highway speed.

There have been a few attempts at spreading the ‘Stop! Refresh! Survive!’ message here in Australia to help combat driver ‘fatigue’, but what has never yet been stated (or would you believe even researched??) is just how badly our breathing in a closed space affects our ability to perform simple driving tasks (driver ‘fatigue’) over the time of a car-trip interstate. The situation is likely to be worse at altitudes above 8000 feet so anyone travelling over the Rockies in the US should be particularly cautious and consider driving with at least one window lowered at all times.

When at rest a human breathes out about 300 mls (around half a pint) of Carbon Dioxide with every breath. In a closed system the size of a typical car cabin (around or below 5000 liters, or roughly 1300 gallons, of volume) in 24 hours a single adult would easily produce enough CO2 to convert over 8% of the total air volume to CO2

At these levels unconsciousness is unavoidable in less than 2 minutes.

Four people in the car means the time taken to guarantee this level of CO2 is reduced to a quarter, or some 6 hours.

At the same time the Oxygen in the system is reduced from ‘normal’ (21% of the total volume) to way below 10% (some of the O2 is converted into water vapour as well as CO2).

At these levels you would die of Oxygen starvation in a matter of minutes, if not seconds.

Combine these two and it is quite simple to see that a driver will be suffering severe affects that affect his driving abilities long before 6 hours are up if he has three mates in the car with him and no fresh air enters the cabin!

Stay Safe – make sure there is fresh air in your car on any long trip!


  1. You make a good point here Love, but you should come visit my office, by 2pm in the afternoon I’m about ready to pass out from all the CO2, there is no circulation of air- makes for pretty brain dead working- so it not just cars- though cars too of course! 🙂


  2. I don’t drive for more than an hour at a time anymore. The last 5 years I worked I was commuting 3 to 5 hours, but that was always alone.

    I do remember on long trip with some friends, to a place called Woodstock, the anniversary of that event is coming up. From what I can remember the air in the car was mostly cannabis, not oxygen. 🙂

    You are right that it is very important to step at least every hour, if you can, to get out, stretch your legs, and breath in some fresh air, unless you are on a highway, where there is none. 🙂

    If I did take a long trip, I would have to stop at least every hour. My bladder gives out quicker now than my oxygen level. 🙂


  3. Rain – next time i am visiting SA i will make it a point to come by your office around 2pm and we can go out into the fresh air for a coffee to refresh your brain 🙂 I hope you don’t work next to a freeway? 😉

    Ed – my sympathies for the rest-room stop issue! 😉 at least you have a chance of surviving long trips 🙂

    I found it amazing that despite the amount of scientific research into driver safety in vehicles there seems to be little to no research on the CO2 – air con recycling problem?

    Oxygen starvation and CO2 respiration in confined spaces has long been known to cause drowsiness and yet i don’t recall any road safetly campaign to make drivers aware of this?

    Quite Strange?

    I may be more than usually aware of the danger since i cannot make any trip to a major population centre within or without my own state that does not involve multi-hour and in some cases multi DAY car journeys. The closest centre anywhere even close to that of Perth’s population (Adelaide) is a 36 hour car journey on open highways with next to no stops in between. 😯


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