Last week I took my 1 month old Model 3 on a long motorway journey (I live in the UK) for the first time. The road was quiet and I followed my usual procedure on such journeys of engaging cruise control at the speed limit. Being my first time with a traffic aware system it took a short while to get used to pulling out in plenty of time so that the car didn't sense the vehicle in front and ease-off, but I found I could live with that.
What was a complete and very dangerous surprise however was when overtaking a truck, without changing lanes, the car got half way alongside the truck and then braked hard to try and drop to a slower speed than the truck - presumably either anti-collision or trying to achieve the traffic aware minimum of three car lengths?
Whatever the reason, on a windy and wet motorway at night it pitched the car violently sideways alongside the truck. I had to straighten the steering and floor the throttle to prevent either driving into the truck or being hit from behind by other traffic.
If this had been on a busier road or at rush-hour then without doubt somewhere behind me an accident would have occurred.
This wasn't a single isolated incident however. I assumed I had done something wrong or it was a freak circumstance, but no...it happened a further 6 times, each time when passing a large truck where the speed difference was quite significant (anywhere between 20 and 40mph difference) Needless to say I stopped using the traffic aware cruise control on that journey and haven't used it since, because I simply don't trust it.
Perhaps if I understood what was happening and why, I might be able to make allowances and drive around it, but it was so random I don't think it is worth the risk.
If anyone has any explanations or had similar experiences I would love to hear them.
Personally I think this feature on the car is unsafe and certainly not fit for purpose.