TACC drafting?

[GoTslaGo]

Sure, for the lead guy. But for the rest, it would be a breeze.

Could drive them like bicyclists. Lead goes for 30 min, then drops back letting 1st follower take lead, and he/she goes to the back. Every 30 minute switch.

Then everyone would get a turn leading (using most energy) and everyone would benefit from drafting. Communication is key. Traffic permitting.

 

[GoTslaGo]

Thinking about it, would a model X benefit from having a model s draft from it?

 

[ohmman]

Could drive them like bicyclists. Lead goes for 30 min, then drops back letting 1st follower take lead, and he/she goes to the back. Every 30 minute switch.

Then everyone would get a turn leading (using most energy) and everyone would benefit from drafting.

Yeah, that was the way I envisioned it originally (I've cycled a bit). But I couldn't pass up on the bad pun.

 

[GoTslaGo]

Interesting to think about the effect drafting could have on the car. From a safety standpoint, it should not be done. (I've taken a few mandated driving classes and the instructors always cite studies on how even with a quick reaction time, the car behind you or on the side of you cannot anticipate quick movement and the likelihood of an accident goes up significantly.)

I have no evidence to back this up except my own experience cycling: when drafting behind a larger rider, I have to be a few inches from their wheel to be in their slipstream. (Obviously this distance is different while driving) Even when cycling, it takes quite a bit of experience to do this safely and perfectly. I can't imagine how someone could do this safely in an uncontrolled environment like a freeway. But if there is a safe way to do it (without pissing off the big rigs) count me in!

With a human controlling the car/bike while drafting we all suffer from the mind-numbing fatigue of follow the leader. Worse with a bike, because you are the engine, the sheer physical exhaustion impacts upon your ability to focus and draft.

With Autopilot (TACC), that is not an issue. It doesn't get tired. Autopilot does respond pretty quickly, and I suspect if you set the follow distance at 2-3 car lengths you could probably get a pretty good draft. One car length, definitely. The risk of autopilot not responding in time is higher with 1-2 car lengths. 3 maybe doable. I wonder if there's any studies out there?

Obviously if it's a caravan and everyone knows what's going on, that would be the best!

 

[brianman]

Sure, for the lead guy. But for the rest, it would be a breeze.

Speaking for myself. I'm happy to be the lead guy. Tesla caravans are quite the spectacle.

It would be fun too do coordinated changes to the follow distance setting as well. Surrounding traffic would think the Borg or Skynet was at play.

 

[Saghost]

Is TACC supposed to react faster than drivers? Honest question.

Of course the cycling analogy is not a perfect one. Everyone has a different threshold for risk. Drafting a truck happens to be too risky for me. For others, it may feel very safe. I tend to think of worse case scenarios like a deer jumping out in front of truck.

I think the myth busters did an episode on cars or trucks drafting. I honestly can't remember their conclusion.

There must be some state trooper or physicist on here that can give there input on experience watching people draft or if it can be done safely.

Does anyone know if it's even legal?

Much, much faster, which is why I felt this was a reasonable question.

The radar measures the exact distance and closure rate to everything in its field of view - 20 times per second.

One of the reasons AP wasn't retrofitable is the new iBooster based braking system - which the wanted specifically for the faster reaction (said to take a third of the time the prior on did,) which is able to develop full braking force in 125 ms (1/8 of a second.)

That means the car can go from cruising along to full fledged panic stop in less than 200 milliseconds - about the time it takes a traditional incandescent brake light to come on after the pedal is pressed.

By the time the human is starting to think they might need to brake, TACC will already have all four wheels at the friction limit, and no semi can out brake a Tesla.

Therefore, the only real risk here is if the semi hits something, or if something comes off the back of the semi.

(Which is not to say I encourage enraging semi drivers, but I figured since the accident risk is low it might be worth asking if we had information about the benefits.)
Walter

 

[mmccord]

I hope you're a big fan of road rage because you're going to get a lot of it doing that.

Never had a problem.

 

[kort677]

I hope you're a big fan of road rage because you're going to get a lot of it doing that.

I've never encountered any sort of road rage from drafting trucks, maybe you're doing something in addition to drafting to incite such rage.

 

[beantobe]

I've never encountered any sort of road rage from drafting trucks, maybe you're doing something in addition to drafting to incite such rage.

Or maybe some truckers just don't care and some do. All it takes sometimes is someone having a bad day and the smallest encroachment on their "personal space" sets them off. Not saying it's justified, but I could see this happening. It would be helpful to get an experienced trucker to weigh in on this.

 

[beantobe]

Autopilot does respond pretty quickly, and I suspect if you set the follow distance at 2-3 car lengths you could probably get a pretty good draft. One car length, definitely. The risk of autopilot not responding in time is higher with 1-2 car lengths. 3 maybe doable.

Some day drafting may be a standard with autonomous driving but I just don't think consumers intentionally testing the limits of safety systems is safe.

 

[swengl]

I definitely draft trucks (on interstates only) using AP/TACC. I see at least 10-15% efficiency increase (if not more) in range and one of the keys is the speed that you are going: If you draft a truck doing 65 vs 75, the savings are huge. I also have not see much road rage from truckers: I try to be courteous and "throw blocks" and that seems to be a good symbiotic way to go about drafting. Rock chips are a risk, for sure. I only draft trucks with good mud (rock) flaps to help lower the risk. I agree with what folks are saying about AP being quicker to respond: a person isn't paying attention 100% of the time, AP is (when engaged).

 

[eye.surgeon]

I've never encountered any sort of road rage from drafting trucks, maybe you're doing something in addition to drafting to incite such rage.

I've never drafted trucks because the fifty cents I would save on electricity isn't worth the high risk, not to mention the rocks to the windshield and hood.

And there's at least one member here that received a ticket for drafting behind a semi after the trucker got pissed and called the cops.

 

[kort677]

I've never drafted trucks because the fifty cents I would save on electricity isn't worth the high risk, not to mention the rocks to the windshield and hood.

And there's at least one member here that received a ticket for drafting behind a semi after the trucker got pissed and called the cops.

it's not about the 50 cents, it's about extending range on challenging hops

 

[Edmond]

I think truckers object primarily to the close following, but secondarily think they're pulling you along costing them more fuel, which is not the case. They're just, eh, 'breaking wind', but think you're taking advantage.

 

[JohnQ]

I think truckers object primarily to the close following, but secondarily think they're pulling you along costing them more fuel, which is not the case. They're just, eh, 'breaking wind', but think you're taking advantage.

This is a common misunderstanding. It actually improves the aerodynamics of the lead vehicle as well ... though not very much. For cyclists it's about 2-3% less energy when you have drafters than when you're riding solo.

 

[e-FTW]

I did this once (drafting a few semis at 55mph), varying between distance setting 3 and short stints at 1. I was on a road trip back to SF from LA, and wanted to avoid stopping before Harris Ranch. This was before going up the hills out of the LA basin. It worked. But the threat of catching a rock chip (at a minimum) was a bit much after a while.
And eventually, the last semi driver made it clear he was not enjoying it, and frankly, I get it.

He has no idea what that car is doing back there, nor should he be expected to trust how you use that car, or its advanced systems. In the end, AP is not infallible, and we should no treat as such. One small glitch, and everyone's day gets much longer. And even if there is no damage on the truck, he is on the hook for whatever follows (police report, insurance, injuries to others, etc.) Hey, it may not even be his truck, or his trailer. And it is definitely his livelihood and his schedule. Time is money in that business.