Merging in to Traffic. (Why Did Car in Front Stop Suddenly?)

Driving to work at 7.30am this morning heading west on Ipswich Motorway M7. Take the Wacol exit to merge on to S30… it's a flyover. The car in front of me slows to check traffic merging in from our right and then accelerates to merge. So, I see this, then I am checking traffic over my right shoulder as I am next to merge. I accelerate to merge then I look ahead, but the car in front of me has suddenly stopped to a halt!! So I rear-ended her.

Both of us fully comprehensively insured, so no dramas there. We stop, exchange details… at first I wasn't sure if my car was drivable as it was pouring water from the front left, but the car computer told me the radiator was fine.. it was the windscreen washer compartment. Its a BMW X5, so the sensors and cameras are smashed, along with the lights etc.

So why on earth did she stop abruptly? She said to me that she didn't know why. She had plenty of room to merge… there was one small truck along that merge.

Anyway, I am automatically at fault because I have rear ended her… because she doesn't know how to merge! So I get to pay my excess…ouch.



        • +42

          Hey saxons,

          If hypothetically a driver in front saw something which made her think it was unsafe to merge so they braked suddenly, would that change anything?

          Obviously, you could have 100 good reasons for sudden braking and 100 bad reasons but as the person behind her does the reason they brake change anything?

          Either way it sucks for you. For the most part I think this is just one of those crappy situations and you move on. Obviously in retrospect you could/should leave big gap or go slower or whatever. I'm sure you'll be more cautious next time.

          • +28

            @Gimli: Same thing happened to me almost 10 years ago but I was the one that braked suddenly because I saw a bus coming at me late. I wasn't prepared to risk getting T-boned by a bus which would most likely kill me.

            The driver that rear-ended me wasn't happy and challenged me why I braked and caused the crash. Literally trying to blame me for being at fault. So I told him that I had to brake otherwise I would get smashed by the bus and that he shouldn't be following me so closely. In the end he had to pay for the insurance excess as he was found to be at fault.

            The moral of the story is. Don't follow too close to the car in front.

          • +1
            • +5

              @Pinchy: There are A LOT of additional circumstances here. It is not anything like this scenario.

      • +34


        Leave more space and be more aware of what other cars are doing around you. Don’t assume that something you would do would be what others would do in the same situation.

        And you replied as I was editing my post, so you locked in my comment as I was changing it.

        Oh, and if you don’t want people to respond… don’t ask questions in a public forum.

        • +32

          Don’t assume that something you would do would be what others would do in the same situation.

          I think the biggest mistake drivers make is assuming other drivers: 1)Know the rules. 2)Know how to drive. 3) Will react the correct way.

          I find if you assume everyone else is an idiot, then you give more room and are less likely to have an accident :)

          • +2

            @dizzle: the problem was though she did start to do something and then suddenly changed her mind for no reason. thats the biggest issue with drivers, the indecision as i can handle drivers that speed and wind through traffic, but its the cars that go slow and then stop and then speed up and then stop, then go to merge, then stop and change their minds etc. Thats the most difficult kinds of drivers as you have no clue whats going on since they dont really know what they are going to do either.

            • +6


              then suddenly changed her mind for no reason.

              Think you mean reasons unknown to OP.

              • @Euphemistic: Apprently he asked her and she didnt know why she did.. Its in the Post.

                • +8

                  @lonewolf: She said she didn’t know why. The cause of the crash was OP not stopping soon enough, not the other driver. The only reason it matters to OP is to learn random reason no 16 for stopping unexpectedly.

                  Not sure I’d be admitting the cause of a crash to a stranger if I made a stupid mistake either.

                  • @Euphemistic: Jeez, when people dont read responses and jump to their own conclusions. Where did i say the cause of the crash was not the OP? And change the conversation from one aspect to another.

            • -1

              @lonewolf: So the other driver 3) didn't react the correct way? (ie the way the OP thought she would react)

              However, the accident was still caused by OP not paying attention to the driver in front and leaving enough space because they made that assumption.

              My point still stands that if you assume others don't know these things, you are less likely (not impossible, I know) to be in an accident caused by other people.

              • @dizzle: I never said the OP isnt still deemed at fault. And no It wasnt the OP thought the way she would react. she herself said she has no idea why she reacted like that.

                And my point was the most difficult kind of drivers are where they dont even know what they are going to do more so than any other reason for their actions. If someone is overtly cautious or overtly aggressive at least you can sort of see it happening, when they dont know what they are going to do then you really have no way of being prepared at all. And my response was meant to be the person above you but it seems to have put your name on it.

            • +3

              @lonewolf: And that is exactly why you keep your distance and NEVER assume you know what another driver is going to do.

          • +1

            @dizzle: assuming, often results in insurance claims as you explain how you were right and the other party was "obviously" wrong…….this is where you grab the pop corn and enjoy the show.

          • @dizzle: Bingo. This is how I avoided t-boning so many idiotic drivers at roundabouts over the years. I now slow down in roundabouts to the point that I know I have enough time to brake to stop the collision when someone should give way to you but they don't.

            • +1

              @DarkOz: You can also see where the other driver is looking at.

              Round abouts are high risk areas, you dont really wanna hang around there long.

              • @Ughhh: She sure looked at me confused after I stopped dead in front of her car honking at her. She didn't even apologise and just drove through in front of me like nothing had happened. I am not even sure she knew she was in the wrong and I saved her car from getting t-boned. This happens too often at roundabouts.

          • @dizzle: Yep! When my father was teaching me to drive 46 years ago, he told me to, “Assume everyone else on the road is a (profanity) and drive accordingly.” Good advice that I’ve passed on to my kids.

          • @dizzle: ^this

            Defensive driving 101

          • @dizzle: +++++++!! best post - 100%

  • +11

    Sounds all good to me. People make mistakes.

    • +2

      Where's the MS paint diagram or at least people demanding to have one.

      1. Straight up though always give enough room to car infront of you.

      2. Install dash cam to upload video footage for ozbargainers.

  • +13

    Seen this happen multiple times.
    Why ? She's entitled to stop for whatever/no reason. Never 2nd guess the driver in front is a competent driver.

    • +5

      I don't think you can stop in the middle of a motorway/free way. I'm pretty sure if someone brake checked me at 80+km/hr it would be carnage. (I try leave a few car spaces gap but even that would not be enough and at busy times it's impossible to leave such a gap because people will just overtake you)

      • +2

        I don't think you can stop in the middle of a motorway/free way.

        Really? Have you never been in a traffic jam in the middle of motorway?

        • +1

          Haha. True

      • +5

        people will just overtake you

        If people do that you just slow down and leave another gap. This was a question asked in my motorcycle training many years ago. Simple answer.

        • I grew up in the country in America and its so different to here. In Brisbane I only ride the bus because whenever I'm in a car its wild. Drivers literally drive right behind other cars. Where I learned to drive you give at least 5 seconds distance, but that might just be because the financial cost to be made even kinda whole there are so much greater and everybody is too poor to pay it. yall gamble your lives away to get to the red light faster.

      • +1

        I don't think you can stop in the middle of a motorway/free way.

        You're just repeating what's legislated. But never assume that people will not break the law because that happens every day.

        I'm pretty sure if someone brake checked me at 80+km/hr it would be carnage.

        You sound like an extremely risky driver.

    • +10

      She's entitled to stop for whatever/no reason.

      I don’t think you are entitled to stop for no reason.

      Unreasonably obstructing drivers or pedestrians
      125 Unreasonably obstructing drivers or pedestrians
      (1) A driver must not unreasonably obstruct the path of another driver or a pedestrian.

      Doesn’t mean you can’t stop for some sort of emergency, you just can’t stop anytime you like. Drivers behind should expect the vehicles in front to stop for no apparent reason.

      • Obstructing traffic would be very different to stopping and moving in stop n go traffic.

    • -2

      You don't ever come to a complete stop that's dangerous and stupid you match the speed of the motorway and merge and keep going, people who think this is fine need to hand their licence back

      • +1

        Not necessarily.

        While merging, you have to give way to the vehicles already travelling on the motorway so you may need to stop to allow them to pass before proceeding to merge.

        • +1

          you may need to stop to allow them to pass before proceeding to merge.

          Unless there is traffic, I don't understand why you would ever need to stop to merge onto a motorway. You've got 100+ metres to judge your entry without coming to a complete halt.

          • @johnno07: So "you may need to stop to allow them to pass before proceeding to merge" then.

            There is also the fact that some drivers are more cautious (or less confident) than others. Similar to people who stop for 3 seconds at a stop sign or stop at a give way sign or roundabout to check if it's clear. It doesn't give me the right to drive through them.

            In any case, the point is moot when the at fault driver drives straight ahead while looking the other way.

          • +1

            @johnno07: There's no guarantee there will be a gap soon enough to not have to stop.

            • @Quantumcat:

              There's no guarantee there will be a gap soon enough to not have to stop.

              I have done a fair few hundred thousand kilometres on the roads and literally have never (outside of heavy traffic) had to stop on an on-ramp.


              Similar to people who stop for 3 seconds at a stop sign or stop at a give way sign or roundabout to check if it's clear.

              None of these things are remotely similar to stopping at the merge of an on-ramp onto a motorway with a speed limit of 110km/h

              • @johnno07:

                1. So you stop when there's heavy traffic but the person OP hit shouldn't stop? How's that make any sense?

                2. How are these things not similar? You are not required to stop at a give way sign nor a roundabout.

                I suspect that you are not the amazing driver you believe you are. More a lucky driver.

                I once went to a seminar with Allianz. They put up a long line with "Good driver" at one end and "Bad driver" at the other end.
                Then asked a bunch of people to mark a point on that line where they felt they belonged as a driver.

                Most people believe themselves to be above average to good drivers. In reality this is not the case at all.

                • +2


                  So you stop when there's heavy traffic but the person OP hit shouldn't stop? How's that make any sense?

                  My assumption was that the OP was not in super heavy traffic, hence was surprised when the person in front stopped. I'm not saying OP is not at least partially at fault (IMO they are). This was also not my point, as it sounded like you are advocating that it's OK to stop while entering a highway while everyone else is travelling at 100+ km/h. Highway on-ramps are designed to allow a person entering to get up to speed and merge safely at speed - that being whatever the speed of the traffic is, up to the posted limit. So, to clarify my point, I can't see any reason to merge at a speed less than that of the traffic around you, save for minor fluctuations to end up in front of (or more likely) slightly behind any adjacent vehicles. If you go the same speed as everyone else, unless it is literally bumper-to-bumper traffic I can't see any feasible reason to stop.

                  How are these things not similar? You are not required to stop at a give way sign nor a roundabout.

                  I'm saying that stopping at an intersection to let perpendicularly travelling traffic to pass is not the same as to stopping on a highway merge while everyone around you is travelling at highway speeds is not equivalent.

                  • +1

                    @johnno07: Fair enough. I must've misunderstood you.

                    Although, I'm mildly disappointed that you didn't respond with a personal attack!!!

                    Please read the rules of "discussing things on the internet" ha ha ha ha

                    Have a great day.

                    • +1

                      @imurgod: Honestly my response was initially a bit snarky and I edited it about 30 seconds after I posted because it was unfair.

                      I've just read the rules, turns out I should have just called you a "******* ****" for not overtly agreeing with me and allowed the conversation to devolve until one of us called the other a Nazi. I shall do better in future!

                      You too :)

                      • +1

                        @johnno07: I will expect you to raise your game in future, you &$##@ing ¥€÷$$

  • +32


    Yes, keep an eye on where you're going.

  • +2

    Unfortunately you are at fault in the insurers eyes.

  • +26

    Its a BMW X5

    Your indicators are okay right?

    • +62

      Brand new, never been used

      • +2

        Wait, he actually paid extra for the "Indicator Bonus Package"…??

        • +2

          He should have spent that money on the auto-braking collision avoidance system instead.

      • +1

        never been used

        That might be actual reason…

        EDIT: Why does it even matter what OP drove… oh wait… (penny has dropped)

      • +4

        Actually I was worried it was just me, But why is this the case. I have noticed it more and more on sydney roads and especially with BMWs and Audis , They change lanes all the time or even turn onto other roads etc without using their indicators? I use my indicator no matter how empty or late night or quiet etc the street is or even in my own driveway as its just reflex.

        • +6

          Because people who waste money on BMWs and Audis are more likely to believe they are more important than other people, and using your indicator is for the benefit of other drivers and therefore a waste of time

      • +2

        maybe it was actually blinker fluid dripping out, on board computer got it wrong

  • +19

    If she "didn't know why she stopped", I'm not sure how much more insight ozbargain can you give u. You weren't in her situation and didn't see what she saw, so she may have stopped for a very legitimate reason, or maybe she didn't.

    I get that you're just having a rant that she could've done something that would've prevented the accident, but like you said, you are the at fault party. So lesson learnt for yourself is just to ensure enough room in front, and be mindful of what the car in front is actually doing (trying not to assume)

    (Maybe instead of saying that you have to pay the excess "because SHE doesn't know how to merge", you should consider having to pay the excess because "YOU didn't leave enough room and made a wrong call on what she was doing".)

  • +58

    the reason she stopped was because she put her foot on the brake.

    • +8

      Amazing, case closed.

    • +2

      aren't we jumping a few steps there :P

      she stopped because of friction

    • +8

      And at that time we assume her brake lights would light up, warning you to slow down.
      But you were looking the other way……,

    • +3

      Honestly mate I must be having an average day because I had a good cackle reading that, thanks for the laugh!

  • +13

    So why on earth did she stop abruptly?

    Doesn't matter why she stopped, the question should be 'Why didn't you stop in time'?

    1) Too close to stop.

    2) Brakes don't work.

    3) Not paying attention.

    • 3 (technically was paying attention - but not to the vehicle in front).

  • +14

    Wouldn't your BMW X5 have a collision avoidance system though? Guess not.

    • +2

      Probably a 20 year old model.

    • no, that's a $20k accessory!

      • Might have saved some money if they're not going to learn from this experience.

      • +1

        Accessory? No.. you need a subscription for these things nowadays.

    • +1

      My 7 year old Camry has that… I guess it is not needed for a high return investment vehicle :'D

  • +6

    Sounds like she's a bad driver.
    Sounds like you're a bad driver too. Sorry op but you can't assume people will drive well, especially merging!

    • +6

      You don't have to be a 'bad driver' to have something like this happen.

      It's just how our driving system is designed. There's a lot of rules of thumb to make it easier to calculate and assign blame. As a result things will happen from time to time, like this. They don't feel fair when they happen to you, but attempting to refine the system to make it more fair would either a) make it more expensive for everybody as more extensive calculations need to be done or b) make it more unfair in some other way.

      For now its just simpler to keep it as: you rear end somebody, its your fault and you're on the hook for the damages.

      • +1

        It's rough for op I agree, poor driving on the other person lead to it all.
        But not paying attention and driving when you shouldn't be could definitely be classed as bad driving.

      • +3

        Easily solved by leaving a sufficient stopping gap and that is well within OPs control.

  • +7

    Nothing like brake checking a BMW ..

  • +6

    I live my life a quarter mile at a time. Nothing else matters: not the mortgage, not the store, not my team and all their rubbish. For those ten seconds or less, I'm free.

    • +2

      I feel like people don't know that a shoulder check is just a slight turn of the head to check their blind spot - what's ahead of you should still be in your peripheral vision. It's not supposed to be an Exorcist head swivel to look out your rear windshield.

      • LOL, agreed. Rear mirror, side mirror, blindspot. Not difficult.

      • To be fair that's kinda what they wanted when I did my driving exam. I did it super quick though as I don't like driving without being able to see what's in front of me. I definitely don't turn all the way around but it is still a bit unnerving not to be able to see what's in front of you for half a second or so.

        • I think in the driving test the idea is to "over-act" a bit to make it super obvious that you are actually doing a headcheck - so you don't fail because the examiner didn't notice.

  • +7

    I've done the same thing as the OP. Car in front had started driving to merge into traffic then stopped. I was watching the traffic coming and "Bang" hit his ass.

    Problem was i assumed he kept going and didn't stop. My fault and the OP's fault to. Doesn't matter what spooked the car in front.

  • +17

    the car in front of me has suddenly stopped to a halt!! So I rear-ended her.

    See, you should have stopped too instead of rear ending them.

    Anyway, I am automatically at fault because I have rear ended her…


    because she doesn't know how to merge!

    Incorrect. It is because you don't know how to keep a safe following distance and pay attention to what is in front of you.

  • +20

    Why Did Car in Front Stop Suddenly?

    Why didn't you leave enough space?

  • +8

    You should be watching what's happening in front of you, and be far enough behind that you have enough time to stop if the vehicle ahead of you stops suddenly. This applies in all situations. You don't know why she stopped, doesn't matter what reason because even if if was for a genuine reason (child running across the road or the car in front of her stopped suddenly as well) you were still going to rear end her with the way you drove. You weren't watching and/or you didn't leave enough distance. 100% your fault and you deserve to pay the excess. Not sure what you thought posting on here was going to achieve. I hope the monetary sting helps you to learn to drive better instead of just crying "it's someone else's fault!" and learning nothing.

  • +13

    because she doesn't know how to merge!

    You've got a funny way of saying "I didn't leave a big enough stopping distance"…

    Good thing you're not a motorcyclist…

  • +2

    If the person that braked doesn't know how the hell would random people on the internet know?