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The Psychology of Range

Range anxiety is such a "charged" issue (sorry!), it dawned on me that TM is shooting itself in the foot with the dash display.

Case in point - showing projected range in big numbers is the wrong focus.

When you go up a hill, the projected range will change wildly, but what does this really tell you? Effectively, it says "if you keep going up this hill until empty, this is how far you can go". But this is a bogus projection, because you won't endlessly go up this hill.

People see the rapid decline in the big numerals , and freak out. Yet this is not at all reflective of what is likely to happen. It confuses a remote possibility (continually high demand), with currently extant reality, (actual juice in the pack), and it exaggerates worry about nothing.

This is like your credit card telling you that if you spend at this instantaneous rate (measured say, at the moment of a large purchase), if you do this endlessly, you will owe a lot. Gibberish.

The better focus is your fuel gauge, (state of charge which decreases slowly by comparison, and is not frightening).

The fuel gauge already figures prominently in the display, but the big numbers for projected range compete for focus, and are alarming.

You focus on the fast changing digits, but they're not the story, the fuel gauge is. Yet your cerebral cortex is built to focus on faster changing phenomena, so you ignore the very stable fuel gauge, and instead give all you attention to that alarmingly rapid decline in digits. Imagine if you saw your gas gauge suddenly spike up or down. You'd think you sprung a leak, and panic. This is not the right UI paradigm.

The other point is that projected range is much less useful than a pair of other numbers for range: Low and High

There are so many variables that affect mileage, the safer thing to do is to provide an envelope for the range you can expect based on how you drive.

So here's a straw man:

Below the fuel gauge, at each end are the low and hi numbers, in a more subtle font.

What does this tell you?

You have 70% charge, and If you drive hard, you can likely go at least 90 miles. With a really light foot, you can go as far as 150 miles.

This inherently gives you useful advice. If you know your destination is closer to High or to Low, you drive accordingly.

Inherently though, you'd never witness on fast changing digits (like the altimeter of a plane in a nose dive), and never have to overcome your subconscious fear with a conscious calculus that "you should ignore these digits as a temporary artifact".

The current approach provokes worry about nothing.

What do you think?

Mark K, this is dead on right! Until my Model S is delivered I am driving a Leaf and it also prominently shows projected range, though its sensitivity is perhaps not quite as acute as the Model S display.

I completely concur that rapidly updated projected range does little more than provoke range anxiety. I learned to completely ignore it after a couple months and rely entirely on how many bars of charge I have left, basically the fuel gauge. But it was terribly frightening at first. I consider it worse than useless because it is so very misleading.

I love your High to Low idea based on the remaining SOC. That would be a fabulous improvement IMO.

Not a bad idea at all - driving an ICE the remaining range doesn't move that quickly until the tank gets low. I like the idea of the extra info at either end of the scale as you suggest.

I think in general, I agree with you that the 'range gauge' needs to be rethought, along with the energy screen. I do think the High Low idea is with merit, although wouldn't the high/low numbers change in similar fashion to the rated range number?

To be honest though, your thread title is really more the issue, its psychology. With an ICE vehicle, we watch the fuel gauge go down, but there is little anxiety b/c we are aware that we can 'fill up' somewhere close. This isn't possible with EVs...yet.

That said, I think 'range anxiety', goes down once you own an EV and realize that on average, you will never come close to 'emptying' the battery. The more I drive my MS, the less I looked at remaining range...

Mark E, my Model S displays the Rated range on the instrument panel not the Projected range. If I want to see the Projected range I have to view my energy graph on the 17" screen. I find that I use my Rated Range is my upper limit of travel. "If I'm really good I could get x miles" then I try to get my projected range to match my rated, and treat it as my lower limit. In really hilly areas I'll switch to average Projected instead of instant Projected to reduce the wild fluctuations.

Though to be honest I don't think changing how range left is displayed will actually affect range anxiety for the massesinconvenience til I learned how to read my range displays and got a feel for where "empty" really was in my S I had some nervous moments. But now this is no longer an issue.

For the masses range anxiety is preventing them from purchasing an EV. This "fear" will only be overcome thru education and familiarity. I like to tell everyone that for 360 days a year I have less range anxiety than in my ICE since I wake up with a full charge, rarely travel over 200 miles in a day, and never have to watch the gas gauge. To me this has introduced new sense of freedom, since I never have to make time to stop at a gas station. For those few times a year I travel >200 miles, yes , I will have to do some planning, but as the Supercharging network spreads this will bcome less and less of an issue.

When taking a long trip, the onboard software could provide a lot of help in managing the charge and charging.

Enter the final destination in the nav system - based on the distance, the car could provide gentle warnings on remaining charge - and even recommendations of potential charging locations.

Rather than expecting each owner become an expert in managing EV charging and range, the car's software could do much of the work - and provide enough warning to reduce the risk of running out of charge during a trip.

bp, excellent idea!

The ideal case would be that the car has a software providing warning on remaining charge based on a driver's current driving and guidance to a closest charging station AND there is indeed a close SuperCharger located on the map we see in the planning stage. However, until that become a reality, MS drivers have to train ourselves (to change the way and mentality that we drive an ICE car) and to train our beloved MS so that we can manage the range anxiety in any given trip. I think that in some sense, driving a MS is like to ride a horse. After a while, you would know how the horse will behave and how you can control her.

LizG +1

back when the Volt came out - my local dealer gave me one for the day. My biggest complaint was that they have a huge display that shows the electric-only range.. which, even if you KNOW how it works, freaks you out when you see 'range - 2 miles'.

They needed 'electric range/total range' to be really obvious.

There definitely is a weird psychology in seeing your total range dropping quickly, even temporarily.

I've come to think that perhaps all of this range talk and range anxiety is just a User Interface issue.

What needs to be implemented in a "fuel gauge", or better yet an "energy gauge". Something that simply indicates your available energy in no more detail than a gas gauge in an ICE, ~ 5% per step on the gague. Of course, this requires easy access to charging as needed, but that is why the concept of the super chargers was launched.

Building future EVs like the GenIII will require Tesla to realize that most drivers only care about aprox. numbers fot the concept of "available fuel", in this case battery power. Having displays indicating the remaining range, down to the mile, will always be subject to fluctuations thus create ambiguity. Perhaps this is just a hold over from the vehicles with MUCH smaller batteries that truly need to tell you that, for example, you only have 8 of your max 11 miles of fuel available.

As the CTO of a large cable company told me when I interviewed for a job there years ago, "95% of our customers are Walmart shoppers. In the end, we can build all of the great stuff we want, but for them to purchase and enjoy it, it has to be simpler to use than your TV remote control."

After a month, mine is going away. I get pretty close to rated. What had concerned me was my ice of 13 years has an alert that goes off at 50 miles and stops displaying mileage remaining. And full tank is a bit over 300 miles. So I consider usefull range to have been 250 miles. Now, in my 60, I start with 188. In my mind, through habit, I consider 50 miles remaining to be the fumes. That would be an effective range of 138 miles. What I have been pleased to learn, is that my habits were learned based on the more imprecise fuel measuring device in the ice. And so ive learned/learning that it is ok to trust the car.

Sloshing gas is harder to gauge than sloshing electrons. Who knew?

All - excellent points, and lively discussion.

As Liz points out, you get confident that you just plug in at home, and you're fine each day - no matter what all the digits say. So you learn to ignore the numbers.

"Learning to ignore" manifests the reality that the current UI is dissonant. It turns out you're fine, but these numbers made you worry for nothing.

@cfriedberg - yes, to be subtle, the hi / lo indicators must take the long view of what to expect, based on averages rather than - this hill at this instant. The inertia in the algorithm is what spares you disconcerting sudden drops.

@bp - yes, great suggestion. An overlay on your nav screen would be very useful. It should show your charge location options, and graphically emphasize the ones it recommends for your current charge and known destination. All of this can be done in the background for the driver, so they don't need to fret over calculating what-ifs. They just drive, and fill when they need it.

@biggator - very true - much of this wrong focus is the stepchild of tiny packs in EVs that came before. The S has much larger packs in all cases. There is no value to extreme extrapolation.

Because TM is leading a disruptive change, they must be very sensitive to wrong perceptions that retard adoption.

A rethink of the range display would really help.

GLlarwill - you hit the essence, much of the anxiety is a UI issue, and it can be fixed with thoughtful design.

You also nailed the holdover effect from earlier EV's with small packs. That dominates the Model S initial UI choices.

Simpler is better here.

I've said this in the Software Enhancement thread, but I would like to see:

1. A digital read-out of usable kWh remaining (not just %), perhaps along with some sort of graphic (bar graph, "thermometer," etc.)

2. A digital read-out of current consumption rate in miles/kWh (not w-h/m), along with a "dial" graphic (similar to the speedometer)

3. A digital read-out of average consumption rate since the last charge, again in miles/kWh.

All of this could fit easily as part of an enhanced Energy App.

I like the low/high idea...but that doesn't answer the big question: "can I get where I want to go?". Others (including myself) think the answer is to integrate nav and energy apps and take into account real-world conditions like speed, outside temperature, hills, etc. I don't know when Tesla will get that done, so I've started an EV Trip Planner (Energy Estimator) that will tell you the energy needed for a given route. That should be in beta in a week or two at http://EVTripPlanner.com - but for now I've posted some tables/spreadsheets with real-world range vs. speed/conditions.

Cliff- yes, the algorithms need to get smarter, and I expect they will. Your efforts to model it better will also help nudge TM to keep advancing the integrated displays in the car.

No matter how smart the modeling though, there will always be a degree of uncertainty. A headwind for example, can wreak havoc with the precision of projected range. (No pitot tube in the grill as far as I know).

For this reason, I believe it is wiser to provide a Lo / Hi envelope rather than a to-the-mile number.

This form of indicator, intrinsically by its design, conveys the message that range will vary based on conditions.

So, in your example, if I want to know if I can get there, I can imagine some helpful ways to display it. Imagine a colored overlay band on the nav screen showing the extents of the Lo / Hi range zones. That band can have an irregular front that's based on elevation, speed limits, and other geo-based data. It could look something like the graphic weather maps that show cold fronts and heat waves.

If my destination is inside the Low perimeter, I'm good. If it's in the band, I drive with a lighter foot. Instead of running numbers in your head, you just glance at it.

That could be actually be pretty cool.

For Tesla to be successful, and continue to increase their monthly sales - they have to appeal to a larger audience of ICE drivers - and make the transition from ICE to EV as easy as possible.

Even when Tesla has the Supercharger network deployed - it is still a different strategy for driving long distances than an ICE and anything Tesla can do using the software, user interface and Internet connectivity to help drivers avoid having range anxiety will help convert more ICE drivers to EV - and generate the sales Tesla will need to be successful.

+1 LizG: You nailed the minor flaw in Tesla's positioning. The Supercharger network is a bit of a red herring. True, and more frequent, range anxiety is when I climb into my ICE for the morning commute to find I only have an 1/8 tank. Filling up during commuting hours can be time consuming. Or, do I just go for it and try to manage the little yellow light? The thought of waking up to a "full tank" is comforting and will reduce at least one of my daily headaches. The convenience of home charging gets a bit lost in all the swirl around the Supercharger network and road tripping.

@LizG: I completely agree. I reduced range anxiety while commuting when I switched from ICE to the S. My commute is 147miles every day and the only reasonably convient gas stations are at the end points. Every ICE I have commuted with provided 2 - 2.5 round trips, depending on traffic conditions. It is that last .5 that gave me significant anxiety twice a week, trying to remember how long I have been stuck in traffic jams the past two days. It took a little while to get use to the S but my anxiety is gone now. I am charged in the morning and have enough excess when I get home that I have stopped paying attention to how much. I did drive more gently a few mornings when we had extreme cold to conserve for the ride back but it turns out it was unnecessary. I must admit that I did not buy the car for long trips so I haven't factored that into the equation.

defmonk and StefanT - Well said. Starting everyday with a full tank is one dimension where the EV experience isn't just at parity with gas, it's actually far better.

At 147 miles per day StefanT, the economic rationale for S is a slam dunk.

Mark K,

Great point. Not only is your tank/low/high display a more useful gauge, but I would go one further and say that the default should be LESS information on range. If the user chooses, they could call up the precise range number, but why would Tesla choose to make that an "in your face" default?

And to LizG who made a great point about getting comfortable with range 360 days/year: but what about our passengers? Our "future" Tesla buyers? They come in our cars, and are made to think range is a big deal that we need to worry about all the time, because of the importance implied by its display emphasis.

Psychology and culture are a big part of UI. They are both cause and effect.

Derek - Well said. It's very inappropriately in your face. This default billboard display is the wrong message to a new customers.

Careful refinement of the UI by TM will reap material gains in adoption.

bp;
For the forseeable future, the audience of possible S drivers = those who have seen, ridden, or driven the car. TM has done all it needs to.

Nick that is a short sighted view. If our forefathers had thought like that we'd still be riding horses.

I plan on driving to Upper Michigan this summer in my S. I have 2 plans

1. If Super chargers are available . No problem. Charge up twice and take maybe an hour or so longer to get there. No big deal since it's free fuel and a nice ride.
2. If Auperchargers not available, take 2 days. Charge in Normal. Stay overnight in Chicago

As I said 360 days a year I don't worry and no I don't just drive in the city. In fact, since we got the S we have gone on road trips aroumd MO every weekend. Pushing the limits of th e car every trip.

True if you travel more than 200 miles everyday and need to get there quick, this may not be the car for you, especially if it is your only car. But, if you haul dirt every day you don't buy a Z4.

The more I think about it, the more it makes sense to simply map the range (Low / Hi) on the nav screen.

This answers the main question at a glance.

Instead of a bunch numbers for you to ponder or crunch, it tells you where you can go with a simple visual.

Also makes a lot sense to display charge point recommendations graphically on the same map overlay.


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