SouthTexasAggie

I had trouble getting Traffic Jam Assist to come on consistently. It turns out the Lane Tracing Assist has to be turned on (I usually keep it off). This is from the manual:

■ Operating conditions of the function This function is operable when all of the following conditions are met:
● The system detects lane lines and the path of preceding or surrounding vehicles.
● The dynamic radar cruise control and the lane tracing assist are operating.
● The turn signal lever is not being operated.
● The vehicle is not being driven around a sharp curve.
● The vehicle is being driven in the center of a lane.
● The driver monitor camera is detecting that the driver is facing front of the vehicle.
● The vehicle is driving in traffic jam on a highway or expressway at approximately 25 mph (40 km/h) or less. (In some situations, such as when a traffic jam starts, this function may be operational at approximately 20 mph [30 km/h] or less.)
● Vehicles with a connected navigation (display audio): Safety Connect is being
subscribed to.
● The driver’s door is closed.
● The driver’s seat belt is fastened.
● Customized setting of the Traffic Jam Assist is not set to off.
● Functions and components composing the system are in proper condition.
● Customized setting of the PCS (Pre-Collision System) is not set to off.
● Customized setting of the dynamic radar cruise control (re-start time extension) is not set to off.

jahnjva

In over 6000 miles it has only come on once and I use Radar cruse a lot. For me it's a waste but it was on the car.

fgina

why does it need data modem subscription? what more does it do other than slow speed adaptive cruise control with lane keep assist? I recently used a rental hyundai that costs half the price. it's able to do the same thing without additional monthly fees.

CommodoreAmiga

I wish it was enabled on more street types. When it does activate I've found it to be useful. I like that it will resume automatically after coming to a stop. If I'm stuck in traffic on an unsupported road I have to manually tap the accelerator or steering wheel button and I the vehicle is more jerky compared to Traffic Jam Assist.

byzatic

One thing it does beyond adaptive cruise: it can smoothly slow the car to a complete stop and then start again.
One thing it uses data for: it can only be turned on if driving on a highway or expressway. I think it uses the map data to determine that safety check.
There may be other things too.

jahnjva

I agree. I have had my car for 8 months and it has only come on ONCE. There are several parameters that have to be satisfied for it to work. I asked my dealer and they tried to get it to activate with me riding in the car and could not. For the amount of times it has come on I think it was a $600.00 waste as was the $250.00 digital key. I won't be renewing either subscription when they expire.

toyotaman7

It allows the driver to take hands off the steering wheel as long as speed is below 40 km/h (25 MPH). as long as:
1- you are on a highway
2- Your speed is below 40 km/hr 25 MPH
3- Dynamic Cruise is active
4- you look forward

You can take your hands off the steering wheel.

The sign on dash or HUD will change to add a moving dashed line in the middle of the lane to tell you it is active.

It is half baked since it only works to 40 km/h (25 mph) and then it shuts down. Like the Dynamic cruise control on 2016 RX in canada that stops working below 40 km/h.

I would not pay for it. It came with the package.

aeromarkco

If you are in a dense metro area and in stop and go traffic on a freeway is completely hands off. This is a life saver or at the very least a big stress reducer. Well worth it as you don’t need to touch and controls with hands or feet below 25 mph or so.

fgina

recently I used a loaner hyundai sonata that has adaptive cruise control and lane keeping assist. it does it without subscription nor data connection. car reminds driver to take over control any time. subscription is a gimmick to get more revenue for features we already paid. so, after 3 years, the Nav will stop working, drive assist will stop working. we are left with a 14 inch slab of light source on the dash.

WellsB

As far as I can tell, the only difference between the regular active cruise control and traffic jam assist is that regular active cruise control times out if you come to a complete stop for too long and one has to press the accelerator pedal or the resume button to get the vehicle to move again. With TJA, the cruise doesn't time out and the vehicle will start moving without user intervention.

Certainly not worth $620, imo, but it is nice to have in heavy traffic on the freeway.

fgina

Unless it frequently quits and tell you, you take over. Just before a potential crash. 😂

wrinkle

So this might be the sign of things after the "trial" period of 3 years expires - these might be the minimum charges to expect, as these are for a 2020 model.

I use Traffic Jam Assist literally every day that I commute, since its for stop-and-go highway traffic that I encounter everyday. It sucks that they connected it with a subscription service, instead of making it work with the Dynamic Cruise algorithms. What might be the technical reason (assuming its not purely a ploy for a subscription money grab ?)


Credit: Poster at reddit, post linked above.

CommodoreAmiga

I think "subscription money" is the primary motivation for Lexus/Toyota. However, the "technical" reason is TrafficJamAssist uses live traffic data, which requires cellular connectivity, incurs some cellular data costs, cloud infrastructure, and engineering support. There are real ongoing costs. Whether their margin on the subscription cost is fair/worthwhile are for individuals to asses. I like the feature, but at $320 a year I think they're grossly overcharging for the benefit.

wrinkle

For TJA, I think only Driver Connect and Dynamic Navigation are necessary - which equate to $ 160 a year per above poster. However, I would suspect Lexus would raise the amounts for the newer RX/NX models, so its fair to expect $ 200 - 300 a year for these features...

The part I still don't understand is WHY TJA requires live traffic data, when it can sense and react to the traffic in front and behind using the Dynamic Cruise sensors. They might have made it to require live traffic data to ensure it only works in 4-lane highways alone (which is why it never activates in city or rural stop-and-go traffic) - which is the part that is a mystery, if true (is it a legal requirement or have they diabolically designed it that way so that users have to pay to have the benefit of the service by artificially requiring live traffic data ?)

asj2024

Which one there is the traffic jam assist? I looked each item up and they seem to be for other things, some of whichinvolve reps (that Lexus needs to pay, which explains the cost).