TACC Fast Response To Cutting In


Now Implemented!


Respond faster to the need to slow down when a car cuts into your lane and you’re following another car using TACC (v6.2).


Currently, the TACC follows the car that is fully in the current lane, even when there is a car overlapping into the lane (e.g. weaving around, or started cutting in). It is only when the car moving in from the side fully occupies the current lane, that TACC slows down to leave the set following distance from the intruder. For an extended period, TACC follows the intruding vehicle at a very unsafe close distance.

This is can be a safety hazard if the driver is not paying attention, and usually requires intervention by the driver, and continuous watchfulness to identify a driver cutting in, and take early avoiding action.

Conversely, when a car is LEAVING the lane, the control logic is reversed: the following distance is maintained until the car leaves the lane completely, and its closest extremity is clear of the current lane. This is clearly conservative and safe and is the logic that should be applied when a car is cutting in also.

Much better than the current logic, would be to monitor the lines of the current lane, and to decrease speed/increase following distance just as soon as another vehicle begins to cross the line on either side.


Improved in successive versions. We consider it implemented now.

lightly edited by moderator
Category: Y3XS Applies to:
     Created 10-Jun-2015


Improved significantly in 7.0 for me, still not perfect, but I'm not sure what limitations they're working with.
    Created 1-Jan-2016
The slow response time is evident in other situation as well, such as when you put your turn signals on to pass and then start to leave the lane, TACC responds by slowing the car as if you were going to run into the car ahead in the lane you are leaving.  Driving directions are also slow sometimes, announcing a turn after you've already made it, for example.  This doesn't happen with other systems, like Waze on my cell phone, and probably doesn't have anything to do with TACC, but it may point to a need to increase processing speed throughout, especially as we move to more autonomous features.
    Created 18-Aug-2015
I don't get that comment ... the car is autonomously controlling speed and following distance ...

The point of the request is that the hardware and software clearly has the capability to take into account a safe distance when a car is leaving the lane in front, and does so very conservatively.  Why it doesn't do exactly the same when a car is entering the lane ahead is baffling, and should be easy to fix.

Doesn't make it autonomous and that's not the point of the request.  Even if it was fully autonomous it would still require alert supervision by a competent driver.

But since the car also has features to react to a collision danger, which run separately from TACC and do a good job of responding to a danger from the side, failing to respond to a car cutting in is - as you say - a hazard that currently requires manual intervention every time.

    Created 5-Jul-2015
I don't want to ruffle anyones feather here but this is not an autonomous vehicle. The owners manual is pretty clear that you should be aware of your surroundings to operate the car.  That goes for every car on the road.  I'll be long dead before I'll have 100% confidence in the cars brain over mine and my experience in driving for over 40 years.  Yes the TACC is smart and will most likely avoid damage or injury but not 100% of the time.
    Created 4-Jul-2015