EVNow
Well-Known Member
For anyone who doesn’t follow TSLA - Tesla company meeting is tomorrow. I would expect Musk to say something about FSD beta. So, tomorrow evening we’ll know whether FSD beta is getting expanded or not on Friday/Saturday.
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Safety Score
- Thread starter ScottNY
- Start date
Just regen. Yes, when you're going downhill regen absolutely takes longer to stop you. Regen applies a specific braking force, less if your battery is cold or full. Since going downhill gravity is applying force to accelerate you forward, the specific braking force from regen will result in a slower deceleration rate. If the hill is steep enough, regen won't even slow you down. That effect is more noticeable with low regen, but given a steep enough grade even normal regen won't stop you.
Why do you state that using just regen on a hill shouldn't result in a ding? That's not correct. Think of it like this: If you have an accelerometer aligned longitudinally with the car, and the car is at rest, the accelerometer will read zero, right? Now suspend the car from a crane and point the car straight down. What does the accelerometer read? It reads one G. So if the car is on a slope pointing downhill, the accelerometer is gong to read somewhere between zero and one G. (I'm not going to get into the math of calculating what angle will result in what percentage of G.) So at some given angle, the accelerometer is going to read .3 G even with the car at rest. At that downhill angle ANY braking whatsoever be it regen or disc is going to result in a hard braking ding, because the Tesla's definition of hard braking is anything in excess of .3 G. So, let's say normal regen results in a .2 G braking force. If you are an a slope that has a .1 component of G longitudinally you will get a hard braking penalty as soon as you lift your foot off the pedal in normal regen. I've found it doesn't take all that much of a slope, relative to the average slope around here, to put you in that position. In a place like Florida that has no hills to speak of, normal regen may never result in a hard braking penalty. Around here, there are hills that are virtually impossible to stop on without getting a hard braking penalty.
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It seems like the simplest way would also be the best. You're not going to have people deciding this, too many man hours of work. This will be a program. What seems simple and makes sense will also be the fairest way. At whatever the decision time is, take the first car with beta requested. (The first person that pushed the button.) Does it have a 100 safety score? Yes: give it Beta. No: go to the next button pushed. This would repeat until you hit the 1000 cars for the day. If you run out of cars with a 100 score, the whole process would start over again for 99. I think this is the most likely scenario because it's easy and makes sense. Why make it harder than that? It seems likely that a minimum of seven days scored will be required, and the algorithm might have a minimum mileage thrown in as well. That's why I'm planning on hitting Friday at just over 500 miles. Why 500? I don't know, it's just a nice round number that I can hit easily.
If I'm correct, I should get Beta Friday night as I'm likely in the first 1000 to have pushed the button. (0400 PDT 9/25) That's assuming that my midnight drive tonight and tomorrow night go as expected. (Once I hit 100 I stopped driving my Y except between midnight and 0100. That minimizes threats due to other traffic and gives me all day to fix any problems that occur.)
All of that said, it seems likely there will be some number of cherry picked beta testers thrown into the mix as well. Employees or people with connections.
Speeding isn’t that big a deal, IMO. Far more important is speed differential in relation to other traffic on the road. If you’re going with the flow of traffic, even if everyone is going 10-20 mph over the speed limit, you’re a far safer driver than one who is his own island chugging along at a fairly arbitrary speed limit forcing everyone else on the road to constantly change lanes to pass you, or if you’re a speedster, constantly weaving between lanes trying to go significantly faster than the flow of traffic. If you’re paying attention and maintaining a safe following distance it is easy to avoid getting any FCWs even if you were going 80 or 90 in a 65. If you’re tailgating and/or have a habit of zoning out you’ll pick up FCWs even if you’re going five under.
AlanSubie4Life
Efficiency Obsessed Member
Sadly I think I was way too optimistic with this. I think it is quite possible that just over 99 (99.5 rounded to 100) will not be good enough.
I’m just wondering when Tesla will start talking about the decimal place. And whether they will start rounding the daily scores to the first decimal place too.
My 99.7 (99.5 with rounding of everything to one decimal place) seems like it may not be good enough! That first day of 98.51 really hurts my true average. I guess in the end we have no idea how many 100 scores there really are.
Of course it’s also possible they’ll postpone release again and make this a long slog.
Getting perfect scores is getting easier now, and even managed to do near perfectly (0.2% unsafe following) in rush hour drives today - so may be able to make it another week; I’m less fearful now. Waiting would be annoying though. And with very bad luck, some other driver can always force hard braking or an FCW, no matter how vigilant you may be.
I think I have circumstantial evidence that TACC alone masks unsafe following. Someone quickly cut across my path today, fairly sure it was a violation, and I only had time to engage TACC. Still ended up with a 0% on that drive. Sadly I forgot to capture the video at the time so I could go back and check it. Maybe we already know TACC masks hard braking and unsafe following?
Didn’t Musk say he was done doing shareholder meetings?
Two things. First I doubt they care about the decimal places. If they did, why average daily scores? Just treat all of your driving as one big event and calculate your safety score from that; that method would be far more accurate. Since they don't care about getting it to the gnat's ass there, why would they then worry about the decimal place for your total score? No, that makes no sense. I think if your total score in the app is reading 100 then you have a 100. I could be wrong, but it makes no sense otherwise. I know I rolled over to a 100 with a 99.51 a couple of days ago. I have no idea how much the days since have boosted that. I just can't believe it matters.
Second, TACC absolutely does not protect you from events. I had to do a lot of driving around to erase events that happened while TACC was engaged. For the purposes of scoring, never use TACC without AP engaged. It's just too easy to get dinged with TACC alone.
Regen applies 0.2gs of deceleration. But you confirm it takes longer to slow down on a hill, so it's not the actual acceleration of the car. It's including the gs the accelerometer sees because the car is on an incline. In your words, it's a constant force independent of incline. So regen will never cause the accelerometer to record more than -0.2gs. On a 30 percent grade the accelerometer will still read -0.2gs, but the car will be accelerating at 0.1g. That is, it's ground speed will be increasing. So you can't get the accelerometer to indicate -0.3 gs with regen alone.
On the 30 percent grade the accelerometer indicates -0.3gs when you are stopped (or your speed isn't changing), caused by apply a force with the brakes that creates -0.3 gs. If you completely release the brakes (and regen), the accelerometer will read 0.0 gs. It's like dropping the car from the crane.
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dburkland
Member
I third this, most of my initial bad scores were because of dings while driving on highways / freeways with AutoPilot / TACC engaged. Even with a following distance of 7 I one time had a 40% unsafe following metric due to people cutting in front of mef and AP / TACC not reacting fast enough. Ever since I switched to manual driving I've gotten nothing but 100 scores.
Elon’s twitter have been awfully quiet about FSD. Awaiting the “1 more week” tweet 
Exactly my thoughts.Elon’s twitter have been awfully quiet about FSD. Awaiting the “1 more week” tweet
Regen causes a certain kW draw from the motors (absent wheel slip), which is a force, not a specific net vehicle deceleration.
If the regen corresponds to 0.2Gs deceleration, and you are pointing downslope with a 0.1G induced decceleration, full regen will add to that and cause 0.3G. When the car is stopped, the accelerometer will still read -0.1G.
Net acceleration versus individual accelerations (forces).
Opposite for me, on AP it’s all 100 days. Manual driving is always dinging me for hard braking (while only using regen) and unsafe following when I’m driving super far behind and only get closer at traffic lights (expected)
Welp guess I’m out for a while with my 99 score
don't say that, it's bad luck.Elon’s twitter have been awfully quiet about FSD. Awaiting the “1 more week” tweet
AlanSubie4Life
Efficiency Obsessed Member
Fortunately you are correct. I’ll have to be very careful with my score the next couple days I guess. Especially FCWs!
I’ll have to play around with this a bit this morning. I’m not convinced. The unsafe following is very sensitive and that person cutting across should have registered. Unsafe following doesn’t matter to the score so should be ok to experiment. I’ll rack up some good following and then try to take advantage of someone cutting in, and get a video clip this time.
The fact that your score was bad when using AP and TACC is expected, but also doesn’t imply you’re getting dinged on TACC/AP (it actually suggests the opposite).
AlanSubie4Life
Efficiency Obsessed Member
Yes, given the quantity of 100 scores lines up with their desires, this makes perfect sense (I’m still thinking they would have done decimal places if there were 10k 100s! - but the number of stans is limited it seems).
And postponing further rollout indefinitely should surprise no one, either. Have to be in the first group, as has been discussed earlier.
Of course, there is always the question of what is a perfect 100/100 safety score? Is that a 100/100? Or a 100/100 that is perfect?
(I think he just means the obvious -100/100 qualifies.)
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The accelerometer only registers the -0.1g of the downslope when you are stopped because the brakes are supplying the required force. If you don't apply brakes (or regen) the accelerometer sees 0 gs. Without brakes the only restraining force is regen which is providing a constant -0.2 gs in the direction of travel. Gravity is accelerating the car 0.1 g down the hill for a net of -0.1 gs. The car is decelerating at 0.1 g. The accelerometer still reads -0.2 gs though, because it zero for freefall minus the constant 0.2 from regen.
Regen isn't a constant kw from the motor. It depends on the speed. Power = f x v = m x a x v, so a = Power / (m x v). Therefore for constant deceleration, the power must decrease as the speed decreases. You can see this happen on the car's power meter as you slow down.
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I mean it makes complete sense to give the beta to those who work from home and drive 20 miles a week to the local store and have a perfect 100/100 score because of that lolYes, given the quantity of 100 scores lines up with their desires, this makes perfect sense (I’m still thinking they would have done decimal places if there were 10k 100s! - but the number of stans is limited it seems).
And postponing further rollout indefinitely should surprise no one, either. Have to be in the first group, as has been discussed earlier.
Of course, there is always the question of what is a perfect 100/100 safety score? Is that a 100/100? Or a 100/100 that is perfect?
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