ADAS systems in cars (driving assistance)

I acquired a 2022 Acura RDX in the spring and the system was enabled by default. I wasn’t crazy about the way it worked on something like a turnpike. If for example I was in the right hand lane, and someone in the adjacent lane to my left suddenly decided to change lanes or exit, either engine braking (a rapid downshift) or vehicle brakes would be applied, sometimes quite suddenly. The distance and sensitivity is adjustable so that can be tuned to your driving style.

At Easter last year, I was in stop and go traffic on the Long Island Expressway and tested it further at low speeds and it was amazing. For several miles I went without me personally touching the brake or throttle. Traffic moved, the car moved and maintained a reasonable distance to the car in front; traffic stopped, so did my car, again at a reasonable distance.

Should you use the system, I suggest you carefully familiarize yourself with its various features so you can quickly enable or disable without having to refer to the manual.

Great! I am only interested in stop and go traffic. Glad it worked well for you.

I have a Subaru with Eyesight and therefore have the adaptive cruise feature.

When I first got the car, I tested the adaptive cruise control in stop and go traffic and it did slow my car and stop it when needed, then resume travelling when the vehicle ahead of me moved again.

Assuming you will still steer to maintain your lane, maybe only adaptive cruise is needed for your plan.

I did just test this once as adaptive cruise is almost certainly not designed for this and is meant for highway travel. My Eyesight also has a lane deviation feature that can be activated which both signals to you when you're drifting right or left, and even gives the steering wheel a "nudge" in the right direction to correct the deviation. Subaru owners with this lane feature also learn quickly that forgetting to signal a lane change will prompt a "stern warning" to remember to signal next time

My 2022 GMC pickup has several pieces of the ADAS system including adaptive cruise control. I also tried it in stop & go traffic and it works well. I usually don't use it in traffic though because it disables the auto engine stop fuel saver feature.

The lane change system works fairly well but it requires some intervention. If I drift out of my lane, a "butt buzzer" warns me and the steering gently nudges the steering wheel. Sometimes it's enough correction but often requires manual assistance.

The auto braking works very well in traffic as does the pedestrian avoidance system. At highway speeds though, it's a different story since it can be fooled under certain conditions.

A few months ago, I was driving on a section of recently repaved road with no center line. A truck rounded a bend ahead of me and the collision avoidance system locked up the brakes! With no center line for reference, the system sensed an immanent head on collision! It scared the bejesus out of me to be sure! Luckily the guy behind me had enough room to stop in time.

IMO, these systems have a long way to go before I'll be willing to fully trust them.

I'd like to know why you explicitly exclude Tesla.

I have a hard enough time being in a passenger seat instead of the driver seat.. I've been tinkering with computers far too long to ever trust one to drive me around. I'm in the final stages of life and doubt they'll have it figured out before I'm gone anyway.

You never know…when we moved into out current home, 1973, we had rotary dial phones. When I asked Verizon, Bell “something” back then, when would we get touch tone phones, the reply was “not in your lifetime.” Well, it happened, probably around 1990.

The best part is my grand niece visiting and calling her best friend. We have an old rotary dial phone and I made her use it for the call.

from watching those old TV shows from the 1950's & 60's with scenes of actors using a rotary dial phone. I can't help but think the time they would save by using Touch Tone would let them add another commercial.

Personally I wish I could permanently disable the auto stop feature.

The purpose, and what many profess to be a benefit, is the fuel savings. That of course is most realized if you do a substantial amount of stop and go driving and has been shown to be about 2% to 8% increase in mileage on the EPA certification test. However, there are other ramifications of the system, often not thought of by the average car owner. I'll list some of the considerations:

1. Because there is a lot of draw and short cycle charging on the battery these cars typically require the use of a AGM (Absorbable glass mat) or EFB (Enhanced flooded batteries). Both of the these types of batteries are at an increased cost to the vehicle owner. Generally speaking, you must also replace them with the same type or possibly encounter compatibility issues with the charging system. There are actually some vehicles that have a dual battery system, the AGM or EFB battery system handling the auto start-stop and a second system handling the normal needs of the vehicle.

2. The starter; typically this is a more complex and robust starter, thus coming at an increased cost, both initially when you buy the car, but also if the starter ever needs replacement.

3. Transmission; every time the engine is auto stopped, the transmission is placed into Park. Then, when the engine is restarted, the transmission is placed into Drive. This by many experts is believed to significantly increase the wear and tear on the transmission. Car manufacturers say "No", but then again they have service departments and parts departments that they need to keep busy.

4. In summer months during the "stop" phase air conditioning may be shut off.

On the downside, some very extensive studies have been done that take into account the ramifications of variables beyond the fuel savings. Things like the cost to manufacture the more robust starter, the improved batteries and their disposal, more robust transmissions, more frequent repairs, etc. Some of these studies say we are kidding ourselves in terms of overall benefit to the environment. "Yes", on any given tank of fuel we provide some small benefit to the environment, but overall we may be harming the environment when we look at the bigger picture.

Thanks for the info.

My truck has a disable switch for the auto stop feature which stays off until I turn it back on.

There are many factors which automatically enable and disable the system. For example, if the A/C is on and the vehicle gets too warm inside, it will restart. Conversely, if the heat is on and it gets too cold inside, it will also restart. If there are too many frequent stop / start cycles, the system will disable itself. It won't activate until the engine reaches operating temp. The list goes on and on.

Still, the information you provided is definitely food for thought.

What we are doing here is evaluating a concept by looking at some of it’s implementations. A badly made baseball doesn’t make all baseballs bad.

During the summer of ‘18 we had an awful hailstorm here. Very many roofs destroyed and very many cars destroyed, including my truck. I don’t know if it is an exaggeration to say that there were almost no rental cars available in Colorado or if it was somewhat better than that. At any rate our insurance got us a 7 series BMW for 3 weeks. The auto-stop (I don’t remember it’s correct name) was flawless and barely detectable. At the end of 3 weeks the insurance company leaned on us to exchange the car for something cheaper and I was provided with a Jeep Compass. If that Jeep’s implementation of auto-stop represented auto-stop I would be opposed to auto-stop.

I rented a 2021 Jeep Compass last May when I was in Denver. I agree completely about that vehicles auto stop. After 4000 miles, for a variety of reasons, I put that one on my do not buy list.

In all fairness, the vehicle was a rental and had not been treated well.

Interesting that your experience is from a BMW in Denver. BMW by the way is one system that is known to be very well thought out. But quoting from a BMW shop manual, I see a list of reasons why the auto start-stop may not work. One reason of interest is “At very high elevation.” The other possible consideration might be “used wrong fuel or too much ethanol.” Denver, at least the last time I was there, dispenses typically 85, 87, and 91 octane due to the elevation.

In extremely hot days
In extremely cold days
Interior temperature has not reached your desired level.
The engine hasn’t warmed up to optimal temperature
Wheels are turned all the way to the left or right
Driving in reverse
The car battery is not fully charged
At very high elevation
Hood is not properly locked
Stop and go traffic
Used wrong fuel octane or too much ethanol

Battery Being Charged can be attributed to to things, on a Jeep.

First on a Grand Cherokee there are two batteries, one is a motorcycle size battery. It can be dead, or have gone bad, or the charge sensor is bad, or the main battery has gone out of warranty at its three years and won't charge enough, unless you drive it for at least 150 miles no stops.

Other jeep, one battery and either the sensor is bad or again, the 3 year warranty is out and you must drive it at least 150 miles to charge the battery to trip the sensor.

The main battery is most likely the culprit. Ask me how I know.
$240 to 350 in my area. Might I suggest go for an Interstate Branded Battery. They're rated tops.

I excluded Tesla because I have practical experience as a passenger in my friend's car. It's my only experience with ADAS so I'm curious about ADAS from other car manufacturers.