Design discussion - a PriusChat style, mileage database

[bwilson4web]

Hi,

The 2010 Prius has been in our hands from just today to nearly 120 days and we've learned a lot. I'd like to use our 'lessons learned' define a PriusChat-style mileage database that we can use to understand what this car actually does. I'm a great believer in consensus, folks offering their best thoughts, on what should be there. First, I want to explain what I mean by a PriusChat style, mileage database.

A volunteer database administrator maintains a master spreadsheet with the manually entered data. Folks volunteer their data in subsequent postings to the thread. Users are requested to provide as much data as they feel comfortable knowing that incomplete fields minimizes the utility of their data. The volunteer has to make value judgements but then they are the one doing the manual labor. This only works if we have consensus that this is a worthy project whose collected data has more value than individual contributions.

Data Fields

• date time - (R) user may override posting date and time.
• city state - (R) identifies geography and climate, user profile can provide by default or user can override with posting city and state.
• gallons - (R) how much fuel was put in car
• brand - (O) if volunteered
• octane - (O) if volunteered
• $/gal - (O) if volunteered
• miles - (R) from tank trip meter
• indicated MPG - (R) from tank trip meter
• average mph - (R) from tank trip meter
• max mph - (O) if volunteered
• flat, hills, mountains - (O) if volunteered, flat < 80 ft., hills are <800 ft., mountains > 800 ft.

So I figure we'd have two, draft tables:

date time	city state	gallons	miles	indicated MPG	average mph
		8.345	458.3	52.1	23

In this mini-table, the date and location would come from the posting. The rest has to be entered. However, the user has the option of providing an override "date time" and "city state," say they are on vacation.

For the OCD among us:

date time	city state	gallons	brand	octane	$/gal	miles	indicated MPG	average mph	max mph	route
		8.345	shell	87	$2.48	458.3	52.1	23	75	f

.

Schedule

Let's first chat about what we can do and how we want to do it. Then in about a week, I'll start a fresh tread with an appropriate title.

I'll also suggest to the moderators that the two existing stickies, our prototypes, be 'unstuck' for a new, unified thread. For my part, I'll volunteer:

• daily to every third day data harvest pass - keeping the master spreadsheet accurate
• 1st posting - includes "How to enter data", current charts, and data entry log
• attempt to keep only current spreadsheet on 1st post - untested, I'll see if I can replace the spreadsheet as updated

I'll also be willing to mentor backup ... a good database needs backup. I have my 'sore points' but let's give this a try, OK?

Comments?

Can older data be entered? Yes, you if you have the minimum we all agree to, I don't care when it is entered.

Usernames or car name be entered? I need someway to keep each vehicle's records unique. I'm open to suggestions.

Bob Wilson

[angelrob]

Originally Posted by bwilson4web

Hi,

Data Fields

• date time - (R) user may override posting date and time.
• city state - (R) identifies geography and climate, user profile can provide by default or user can override with posting city and state.
• gallons - (R) how much fuel was put in car
• brand - (O) if volunteered
• octane - (O) if volunteered
• $/gal - (O) if volunteered
• miles - (R) from tank trip meter
• indicated MPG - (R) from tank trip meter
• average mph - (R) from tank trip meter
• max mph - (O) if volunteered
• flat, hills, mountains - (O) if volunteered, flat < 80 ft., hills are <800 ft., mountains > 800 ft.

Usernames or car name be entered? I need someway to keep each vehicle's records unique. I'm open to suggestions.

Bob Wilson

Thanks, Bob. I'm not sure if the table/db can do it or not, but it would be nice to see the calculated mpg and %different as well. Probably username would be the easiest way to make the records unique. Can the db be sorted as well/at will?

I'll chat with you to discuss what being a backup entails.

Robbin

[bwilson4web]

Originally Posted by angelrob

Thanks, Bob. I'm not sure if the table/db can do it or not, but it would be nice to see the calculated mpg and %different as well. Probably username would be the easiest way to make the records unique. Can the db be sorted as well/at will?

I figured the 'database' would be an excel workbook ... initially. The fields provided would be used to calculate missing fields, if possible. Regardless, the workbooks would have multiple charts and possibly derived spreadsheets as needed.

I plan to attach the spreadsheet to the first posting.

Originally Posted by angelrob

I'll chat with you to discuss what being a backup entails.

I figured it would work like this:

• original poster - with read-write of the database, they are the primary admin.
• all admins - by default since they have the ability to edit as needed BUT they have a different responsibility ... 'herding cats.'
• backup - application is by "value added engineering" as in taking a copy of the workbook and creating a new report; stepping in if the original poster is absent (negotiated with moderators); and/or starting the next thread in say 3 months
• thread expiration date - on Oct 1, 2009, a thread starts with a title "[09/10/01 - 09/12/31] PriusChat Mileage Database" The last two weeks of December, the community would negotiate or nominate the next quarter admin.
• For the good of the community and sanity of the admin, responsibility has to change ... to be a shared project.

This my opinion today but often practice reveals unexpected reasons for making a change.

Now I have history with some great OCD Prius owners and I'll send them a PM and ask if they would help kick-off the database. Obviously I'll have added mine. Then we'll see how well it works.

One thing, I've visited other web sites, EPA and FUELY, and used their public data for specific reports. But I have no interest in using any of that data or other web site data in this report. The practical reason is it takes too much effort to capture.

I have no interest in 'trolling for users', which is why I'm thinking of dropping the $/gallon individual column. This is a FUELY and EPA field. I'm thinking of staying within the vehicle engineering units.

Now my primary mileage database is at MyHybridCar but I post copies at:

1. Ecomodder - the best site for applied engineering. If not Prius gear heads, they understand the engineering and it is good to have peer review.
2. EPA user data - although I don't care for the way they 'hide' other user data from user analysis ... I can't see the individual records of other, same year, Prius owners ... having access to the user MPGs is better than nothing.

This is the model I want to encourage: (1) keep a primary source, and (2) copies here for fleet analysis.

Bob Wilson

[cantgoback]

Hi Bob,
First I have to say this is a noble idea you have. But I don't quite get what you're trying to achieve with this, which I hope you can help me to understand better. Obviously the primary goal of it is to gain some new insight or confirm or disprove common beliefs on what affects MPG by collecting and analyzing collective data. But it all hinges upon which pieces of data should we be collecting, right? There are more than a few factors that influence MPG -- tire pressure, type of tires, size of wheel, driver habit, road & weather conditions, hilly vs flat, wind, etc... What do you hope to learn from all this? My guess is you're trying to study if/how environment, temperature, and speed affect MPG? Can you please clarify why/ you chose the specific data fields you chose? I'm not trying to dissuade you or anything like that, just trying to understand for myself.
Thanks in advance.
Robert

[Fred_H]

I vote for adding Outside Air Temperature.
If there is room left, I would also vote for Average Trip Length.

From my personal observation, these two things are the biggest factors influencing mileage that many new Prius drivers do not take into consideration, and then wonder why their mileage is so different than other's.

With concrete data for these factors, we could calculate how much they affect mileage, on average, and then better compensate for them when comparing mileage.

[a64pilot]

I think OAT is relevant as well as tire pressure, if I understand the goals. Average trip length obviously is important, but I think harder to quantify.
However, I'm in if you will have me, my background is hitting "test points", so I think I could handle this. Mostly I'm interested in seeing the data, but not smart enough to compile it myself.

[cpatch]

I'm not sure if average mph is that useful by itself. What about adding percentage highway?

[bwilson4web]

This was my thinking, at least for the first quarter, Oct 1-Dec. 31:

outside air temperature - we had that over at GreenHybrid but over several weeks, the temperature changes and led to a lot of 'slop.' I figured to use the NOAA climate data for City State points to get minimum and average and a uniform formula for the likely morning temperaturel. It might work and takes the burden off the data submitter.

trip duration - as an experiment, I used miles/day looking at the 'FUELY' data and I think it has some merit. Divide by say 2.5 trips per day and I suspect we're reasonably close. But obviously there could be outliers. My thinking is try this for the first quarter and if the data shows too many outliers, will can add it as a user settable option.

vehicle operational stuff - tire pressure, driving style (aka., cruise control, foot-ECO, foot-NORM, foot-PWR, PnG,) tire brand, even the gasoline stuff, these may be pushing the window. It isn't that I'm opposed to these as optional fields as much as I remember the limits of their participation. Personally, I prefer to see individuals do their own "A" "B" "A" tests on these single points and bring their results as a study, like the recent "glider" tire pressure study. It is one of things I most admire at Ecomodder. But I'm not hard for or hard against these as much as what I saw in the data at the old GreenHybrid, FUELY, MyHybridCar and EPA databases.

As for what we might learn? That is the beauty of the experimental method. We may or may not gain insights. But without data, we're all just offering speculations. For example, the SAE report on PnG. Some of their results I was able to replicate and confirm, they got 24% improvement in one set and I got 25%. But their 89% improvement is not something I've been able to replicate. To me an 89% improvement in PnG over the equivalent steady speed remains a speculation.

My thinking is I'm willing to 'be the goat' on this study for 90 days, Oct 1-Dec. 31, and lets see what comes out. If nothing else, the "lesson's learned" may help others improve upon their own databases. If it becomes useful, may be we can find someone to cover Jan 1-May 30. We can 'institutionalize it.'

Bob Wilson