Unsafe overtaking is one of the major causes of deadly head-on crashes. It is not merely a question of whether the road markings entitle you to overtake legally – but much much more. We would like to explain this by sharing a insightful discussion with a prominent road crash investigator:
Question:
Good day Sir/Ma’am, I will be going on the road to Gauteng Province and would like to remain as safe as possible on the road. Seeing that many accidents happen due to head-on collisions, I have a question about safe overtaking distance and overtaking time. If a 22m long truck is driving in front of me at 80km/h and I need to accelerate from 80km/h to 120km/h, how much time and distance is legally recommended to safely pass that vehicle on a level surface?
Answer – a Wide range of factors to consider
Herewith, a reply as requested:
The question is more technical than you might realise, but I will try to answer and explain.
Your question includes inadequate variables to actually answer – here is why:
If the truck is 22m long and driving at 80Km/h, what would you initial speed be – also 80 Km/h (waiting behind it) or higher (approaching)?
If you are behind the truck (also going at 80 Km/h) how fast can your car accelerate (in top gear, one and two gears down)?
If you are going on holiday, will you car be empty (performing normally) or loaded (people and luggage, trailer, caravan, etc)?
If you are behind the truck and want to overtake, based on DISTANCE how would you judge the available distance (reference court cases clearly confirm that people cannot accurately judge speed or distance).
If you are approaching and want to overtake another truck, with an approaching vehicle some distance away – how fast is that vehicle going?
If that driver sees you overtaking – will they move over and slow down to allow you additional time/space or will they maintain speed and position and/or even accelerate and flash their headlights at you “because you are wrong?”
Is this a daytime or night-time scenario, on a flat road, an uphill or downhill? All could affect the resultant effort.
See – there are just too many variables to answer this question off-the-bat, like that.
You are also asking about the “distance legally recommended to pass safely.” There is no such “legal distance” but I can tell you that the ILLEGAL distance would be one where you collide with the other vehicle.
Perhaps a better question would have been to ask what factors you should consider when overtaking?
In that case – all of the above. But – this is a very subjective thing and no one could (or would) tell you that you should, could, must or may overtake a 22m-long vehicle, without being right next to you in the car, knowing the car and its capabilities and yours and seeing the situation.
Stan Bezuidenhout
Forensic Collision Homicide Reconstructionist
Follow-up Question:
I thought of asking the people who oversee safe travelling. So, if I can figure this out (the hard way), how can SANRAL allow that short distance to be a legal overtaking area if doing so might pose such a risk? Also, that overtaking zone is right on a bridge, where the possibility of cross winds can also affect safe passing of vehicles.
Response:
Remember – a broken line is an area where you MAY overtake but whether you CAN or not is another issue.
Imagine if you are driving a (slow) scooter and you encounter a 60m-long abnormal vehicle there. You would be ALLOWED to overtake, but you would not be able to ACHIEVE it in that distance.
Also – a guy with a Ferrari could easily do it.
Or if one is driving at 110 Km/h and the other at 120?
The distance of a broken line is NOT based on any promise that all vehicles would be able to overtake all others.
I fully understand your question but I think you’re setting yourself up for disappointment.
As I said – too many variables to consider. I would just be overly cautious.
Hope this helps.
Follow -Up Question 2
So if i get involved in a collision or given a fine in piraticular area, I will still be the party at fault, even thought that is a special circumstance area where one vehicle must either drive extremely slow or the other is extremely powerful? That does not seem to be a very fair trade for an average road user.
Thank you for the time you have afforded me and I hope I did not cause too much inconvenience.
Answer:
No. You seem to be putting the cart ahead of the horse.
A broken line is not an indication of some (kind of) authority to overtake, applicable to all possible solutions.
It is merely an indication of an area where – if it is safe to do so – you would be allowed to overtake.
The converse is true: If there is a solid line it means that – even if you think it is safe – you may not overtake.
If you were given a fine, it would be a completely different story – the fine would not be for “not overtaking quickly enough.”
Road safety is not about “fair trade” and it cannot be seen this way. All road signs are guides or instructions, essentially.
Guides are there to give you some freedom and regulatory signs to prohibit you from some action.
Equally, if there is a speed sign of 120 Km/h but it is raining very heavily, the sign will remain but you have the additional responsibility to “keep a proper look-out,” to “operate your vehicle with due regard to the prevailing conditions” and to “take all reasonable steps to avoid a collision.”
I happily answer because many people try to use “obvious” and “logically” in their consideration of more complex legal issues.
In short – you may only overtake when it is safe to do so and only where there is a broken line. Any deviation from this will likely attract risk, danger or a fine.
Hope this helps.
Stan Bezuidenhout
Forensic Collision Homicide Reconstructionist
Also view:
Safe Overtaking and Road Safety
