I am a little confused or dumb about Traffic Jam Assist. I definitely have the option. I have both Dynamic Cruise Control (DCC) and Lane Tracking Assist (LTA) active. My RX is 7 months old and I have never seen Traffic Jam Assist activate, although I have the required stuff turned on.

I pretty much am never in a line of traffic that starts to slow down to a very low speed where my car automatically slows down too.

An example of what I typically experience is I might be driving 50mph and come upon cars that might be moving 10 mph or less in heavier traffic. I don’t feel comfortable letting my car suddenly reduce its 50mph speed down 10 mph, so when I get close to the slower traffic I use my brakes and of course this deactivates both DCC and LTA. After I have slowed my car down ~10mph with the foot brake, I cannot reactivate the DCC and LTA, so that the Traffic Jam Assist will work.

I also have the same problem if I come upon a stopped car in a line of traffic. When I use my brakes to stop, I cannot reactivate DCC and LTA to make Traffic Jam Assist work.

Does TJA work in the conditions I experience? If so, what am I doing wrong? I would appreciate any help or advice anyone can give me.

Thanks.

 

It only works on highways, not city streets and only when you are in adaptive cruise control

 

Thanks, that clears some things for me. Knowing it is only for highway traffic, not cities and towns, clears up a lot and changes my expectations. I am using Adaptive Cruise Control, not Dynamic. I will correct that in my post.

 

There is an extensive explanation of Traffic Jam Assist in the manual.

 

I actually looked at and have referenced the Traffic Jam Assist section in the manual a few times, but I never got the distinction that it was solely for highway traffic jams. I will delve back into the manual again and see what I can learn. Where I mostly drive, my idea of a traffic jam is in towns. :-)
Thanks.

 

 

WellsB, thanks much for taking the time to post this. I did read that section previously and thought it meant only that the TJA activates at 25mph and would still work in town traffic. I guess from day one when I read about TJA, my narrow vision of how I viewed a traffic jam is in stop and go traffic in towns and cities. Lexus has a couple good TJA videos that I watched and all were on highways, but it still never dawned on me that TJA was just for highway traffic jams. I am not a dumb guy, but I sure feel dumb related to how I thought TJA works.
Again, I appreciate you taking the time to help me.

 

The are certain criteria that have to be met for it to activate. It doesn't matter if your in a city or on a highway. When your in adaptive cruise control and hit traffic, after the car slows to about 25mph it automatically kicks in. It won't work at faster speeds no matter how congested the traffic is. Mine activates hardly ever. The 1st time it did I was in New York City.

 

You can activate adaptive cruise (and therefore LTA) at any speed. I activated them at a stoplight several times yesterday for funsies. It defaults to 19mph setpoint if you activate it below that.

 

N4TECguy,
I just saw that in a video a couple hours ago. I actually got into my car and drove around to check it out. I did get behind stopped traffic, then activated ACC while stopped and it work great. I did have to push accelerator at 19mph when traffic started moving faster, which is the way it works from standstill. Car responded as if I were using TJA, but I never saw any alert showing that.

Thanks for the info. I would venture to say a lot of us don’t know about that feature.

 

You can increase the speed setpoint at any time by using the cruise control buttons, or continue driving with your foot on the gas.

Also not sure about this, but I think I recall TJA changes the colors of the display when activated, in case you missed the initial popup saying it is activated. The normal colors below the speedometer are somewhat more grey and monotone, when TJA turns on it becomes blue.

 

When TJA is active, the symbol adds a blue bar with diamonds to the CC symbol.

TJA:

No TJA


from manual;

 

Thanks, WellsB.

 

I've used it in a town with 40 mph speed limit. It waits a bit too long to apply the brakes for my comfort (got too close and braked fairly hard), but it worked. I probably will not be using it much.

 

Did Traffic Jam assist actually activate in city or only dynamic Radar cruise control?