Monday, January 23, 2017

Summer 2015 License Plate Game Report

Summer 2015 License Plate Game
By Mark Kloha
© 2015

The Hypothesis
The probability, frequency, and difficulty of finding a license plate from any given state is related to three variables – population, distance, and per capita income for that state.  The number of license plates that I find from any given state will be highly correlated to a combination of these three variables.
Background
I've been playing the license plate game since I was a kid.  We would go on fairly long summer trips to various places across the U.S. as my dad was a teacher and had the summers off.  I spent a lot of time in the car and needed something to do.  When I was a kid, there were no iPhones or apps.  I had a notebook and a pen.  I would make my lists of the states and check them off as I found them.  I would do this every summer on our trips.  
When I was a kid, I had made the connection fairly quickly between frequency of a license plate and the distance and population of that state.  I remember I always had a hard time finding Idaho.  It was far away and not a lot of people.  I didn't have any problems finding California.  Even though it was far away, it was and is the most populous state.  
Recently, I was playing this game with my wife and kids, I commented that there were a few southern states that were fairly difficult to find.  The states that I could not find were southern states that were not that far away from Michigan and are not considered low population states.  Trish suggested that it was the economy of that particular state.  I considered it for a while and it made sense.  
Now that I am older with kids of my own, an iphone with some cool apps replacing the pen and paper, this summer we are on the hunt to find license plates from all 50 states and to track how often we see license plates from other states.  
Methodology
Timing
I will begin Wednesday, May 20, and go through Tuesday, September 8 (Memorial Day Weekend through Labor Day Weekend).  For the purposes of this research, each ‘week’ begins on Wednesday and ends on the following Tuesday.  This timing allows the weekends to be grouped together including the Mondays of holiday weekends such as Memorial Day weekend and Labor Day weekend.
Tools –
When tracking license plates, I will be using an iphone app to track when and where I see a license plate.  The app I am using is “License Plate Zone”.  This app allows me to log any state and any license plate multiple times.  Most license plate apps will only let me log a state once. 
Trish does most of the driving on the weekends and in the evenings.  I will be able to log the license plates quite effectively.  If I am driving and see an out-of-state license plate, I can press a button on my iphone to talk to Siri through a Bluetooth-hands-free connection and have Siri make a note of what license plate I just saw.  Then I can enter the information into the app later on.
How I’m Counting
I am only counting the official 50 States in the United States of America minus the State of Michigan.  I am not tracking U.S. districts and territories.  I am not tracking Canadian provinces or territories.
Some states only require a license plate on the back of the car.  Some states require a license plate on front and back.  It is possible for a car to have two different plates from two different states.  This can happen if a person lived in say Hawaii for a while, brought their license plate back (or even their car) to a state that only requires a license plate on the back, and then they kept the license plate on the front.  For the purposes of this study, front license plates do not count.  That’s right – front license plates do not count.  Last summer I did see a Hawaii license plate on the back of a pickup truck right here in mid-Michigan.  I have seen a number of Hawaii license plates on the front – while these are rare in of themselves, these front license plates will not be counted.  I cannot make an exception for Hawaii because then I would need to make an exception for all front license plates.  Technically, what counting the front license plate would do is increase the population of that state to anyone who had ever lived there and just happened to keep their license plate, and I have no way of adjusting the population factor to accommodate these front license plates.
License plates from semi-trucks, U-Hauls, etc. do not count.  Depending on the state laws, it is more beneficial for certain types of truck companies to be registered in various states.  I’ve seen a lot of semi-trucks with Maine license plates but very few passenger vehicles with a Maine license plate.
I will do my best not to double count license plates.  For example, on my way into work, I see a car parked on the side of the road and it has a Tennessee license plate.  I see this car on my way into work every day.  If I’m at a campground, it is possible that there are campers from out of state there.  As we move around the campsite, I will not record a license plate every time I see the same vehicle again later on. 
Where I’m Counting –
I am only counting out of state license plates while in Michigan.  Our summer travel plans are mostly in Michigan.  We have several weekend camping trips planned throughout Michigan.  Also, I will be looking for license plates just in our daily routines.  We will be going to Columbus, Ohio and Indianapolis, Indiana in June and August respectively.  While out of Michigan, the license plates that I do find in these other states will not be counted. 
Variables -
I have three variables – population, distance, and adjusted per capita income,
Population
The population data is from the U.S. Census Bureau and its Estimated 2014 Population.

Per Capita Income and Cost of Living
The Per Capita Income is from Wikipedia which in turn uses American Community Survey 5 Year Average as its source.
While I was putting together this information in an Excel spreadsheet, it occurred to me that the states have different costs of living and that I should take that into consideration.  So, after a Google search I found a “Cost of Living” index for each state.  I then applied this index to each state’s per capita income.  I will be testing for both the per capita income and the adjusted per capita income.

Distance

The fourth variable is distance.  The app I am using lists the latitude and longitude of where I found that license plate.  Then I had to figure out how to calculate the distance from that particular point back to their home state.  I needed to define a single point in the other state to calculate the distance back to that particular state.  I considered the following options for points in the other states:
1.       The state’s capital
2.       The state’s largest city
3.       The state’s largest metro area
4.       The state’s border
5.       The state’s geographic center
6.       The state’s population center
7.       Some average of the above methods

In some states, the capital, largest city, and largest metro are all the same; in some states, all three are different; in other states, two out of the three are the same; in some states, the largest metro area is sprawling into another state. 
For the final statistical analysis, I am using the distance to the largest city as my distance variable.
Da U.P.
Michigan has an Upper Peninsula!  I know.  I went to college there.  I did not use the U.P. border for any measurements to any other state.  Approximately 80% of Michigan’s population lives within a two hour drive of Michigan’s southern border, and 90% live within a 2.5 hour drive of Michigan’s southern border.  For people visiting Michigan, the large majority of these visitors will come through the southern border rather than through the U.P. border.
Shortcuts through Canada and the Lake Michigan ferry boats
For the purposes of computing distance from Michigan to other states, there were no shortcuts through Ontario, Canada to get to the Northeastern states.  To get from Michigan to the New England states, it is quicker to travel through Ontario, Canada; however, all distances are based on traveling through the United States.  The one exception to this rule is Alaska.  It is possible to drive to Alaska, and then it is necessary to drive through Canada.
To get to Michigan from Wisconsin, Minnesota, or other western states, there are two car ferries that go across Lake Michigan.  The Lake Express goes from Milwaukee to Muskegon in 2.5 hours.  When calculating routes in Google Maps, Google Maps always said the quickest way to some places was via ferry specifically the Lake Express.  The S.S Badger goes from Manitowoc, WI to Ludington, MI in 4 hours.  The routes to Wisconsin were based on driving through Chicago and not the ferry boats.
Distance to Hawaii Calculation
It is possible to find a car with a Hawaii license plate on the back in the mainland and even right here in Michigan.  I’ve seen one.  It is impossible to drive to Hawaii.  I completely realize I am stating the obvious; however, this obvious fact causes some concern as to whether or not Hawaii should be included in the study.  Alaska has a population, per capita income, and a drivable distance even though it is through Canada.  Hawaii has a population and per capita income but no drivable distance to Michigan.  If I were to include Hawaii in this study, then how should the distance be calculated?  If I use the actual distance from Hawaii to Michigan of 4,500 miles, then this assumes that the distance is drivable.  If it were drivable, then Alaska should be more difficult to find than Hawaii. 
It is possible to transport a car from Hawaii to California by boat.  It costs approximately a thousand dollars (give or take a few hundred dollars) and takes ten days.  http://www.matson.com/pov/booking/shipping_rates.htm
There are a few possibilities for dealing with Hawaii:
1.        Not include Hawaii in the study
2.       Convert all the distances to a “time” variable. 
3.       Convert the shipping time and costs from Hawaii to California to a “distance”. 
I would like to keep Hawaii in the study.  I do not want to convert all the distances to a driving/traveling time.  Driving time is quite subjective with so many factors such as how many people are traveling, are they traveling 24/7, are they driving slow, fast, speed of traffic, etc.  I did not want to try to account for people’s personal driving habits. 
I came up with a method to convert the time at sea to a driving time.  It takes 10 days to ship the car.  The trip will take 10 days, and assuming that an average driver could easily drive 500 miles in one day, then that means the entire trip has been assigned a mileage of 5,000 miles from Hawaii to California, and this will get the vehicle from Honolulu, Hawaii to Los Angeles, California.  The distance from Detroit, MI, to Los Angeles, CA, is 2,270 miles.  So, adding the converted time on the boat to miles with the actual mile from Michigan to California, this gives 7,270 miles. 
As mentioned earlier, a license plate on the front of a car does not count.  I have seen many Hawaii license plates on the front of cars; however, the back license plate was the state the driver currently lives in.  Counting the license plates on the front actually increases the population factor of the state.  Not only would you be looking for current residents of that state, you would be looking for past residents who kept a memento of their stay their tattooed to the front of their car.

Quick Summary
1.       I am only tracking the official 50 States – not including D.C or other U.S. territories.
2.       I am not tracking Michigan.
3.       Distances are measured from Michigan’s southern border only.
4.       Distances do not use the short cut route through Canada to get to the New England States.
5.       The distance to Alaska is based on driving through Canada.
6.       Only license plates on the back of a vehicle count
7.       License plates on semi-trucks and rentable trailers/trucks do not count.
8.       I will be tracking both the frequency, date, time, and location for where and when I see an out of state license plate
Results
During the 16 weeks, I traveled, 9,870 miles within Michigan.  I logged 1,400 out of state license plates.  The top 5 were:
Illinois
Ohio
Indiana
Florida
New York

These 5 states made up over 50% of my sightings. 

The bottom 5 were:

Idaho
Delaware
Maine
North Dakota
Hawaii

Except for the bottom 5 states, I saw every state at least three times.  I saw Idaho and Delaware twice; Maine only once; and no North Dakota or Hawaii.  I was a little surprised that I did not see any North Dakota plates.

The days of the week that I saw the most out of state license plates in order:
Sunday
Friday
Saturday
Monday (Labor Day and Memorial Day both saw spikes compared to the other Mondays)
Thursday
Tuesday
Wednesday

For the following statistical computations, the independent variable is Frequency - how many times I saw each state.  The three dependent variables as mentioned earlier are population, distance, and per capita income adjusted.  I did do some correlations with just the per capita income but this was not used in the multiple regressions.
Correlations
Using Microsoft Excel, I ran independent correlations between the following four variables and got the following results –
Population:  40% correlation
Distance:  -27% correlation
Per Capita Income (PCI):  0% correlation
Per Capita Income Adjusted (PCIA):  23% correlation

So, population is the most significant variable.  The distance factor is a negative correlation.  This means it is an inverse correlation – the closer the state then the higher the frequency.  I found it interesting that I got a 0% correlation on the PCI but then it jumped to 23% once I adjusted the state incomes based on the Cost of Living Adjustment factor.
When I take out the top 5 states and the bottom 5 states, I get the following results –
Population:  59% correlation
Distance:  -29% correlation
PCI:  16% correlation
PCIA:  37% correlation

In this analysis, the PCIA has a higher absolute value correlation than the Distance variable.


Multiple Regressions
Using Microsoft Excel, I ran several multiple regressions.
For Population and Distance for 49 states
Multiple R:  .471
R Squared:  .222
Adjusted R Squared: .188

Pop t-stat:  2.961
Distance t-stat: -1.946

For Population and Distance without Hawaii – 48 states
Multiple R:  .537
R Squared:  .288
Adjusted R Squared:  .256

Population t-stat:  3.268
Distance t-stat:  -2.910

For Population and Distance without the top 5 and bottom 5 (39 states)
Multiple R:  .698
R Sqaured:  .488
Adjusted R Squared:  .459

Population t-stat:  5.328
Distance t-stat:     -3.164

For Population, Distance, and PCIA with 49 states:
Multiple R:          .483
R Square:             .234
Adjusted R:        .18

Population t-stat:  2.966
Distance t-stat:  -1.182
PCIA t-stat:  .825

For Population, Distance, PCIA without Hawaii (48 states)
Multiple R:  .550
R Squared:  .303
Adjusted R Squared:  .255

Population t-stat:  3.287
Distance t-stat:  -2.433
PCIA t-stat:  .960


For Population, Distance, PCIA without the top 5 and bottom 5 states (39 states)
Multiple R:  .753
R Square:  .567
Adjusted R:  .530

Population t-stat:  5.667
Distance t-stat:  -2.458
PCIA t-stat:  2.526

My new variable

If I create a new variable - (Pop*PCIA)/Distance and run a correlation of that with Frequency for the 49 state, I get a 91.7% correlation!!

In the world of academic Geography, they like to be all scientific and stuff and they have various equations to calculate interactions between two places.  It’s based on Newton’s law of gravitational attraction F=m1*m2/d2.  Gravitational Force is equal to the mass of object 1 times mass of object 2 divided by the distance squared.  This equation has been adopted by geographers to the following:

Demographic Gravitation is DG = p1*p2/d2
Demographic gravitation is equal to the population of place 1 times the population of place 2 divided by the distance squared.  The other equation is Demographic Energy – DE=p1*p2/d.  Demographic Energy is equal to the population of place 1 times the population of place 2 divided by the distance.

For the purposes of this research, I have adapted these equations further.  I created three new variables:

                P/D = Population/Distance
                PDIA = (Population*Adjusted Income)/Distance
                PIA= Population*Adusted Income

Since I was focusing just on the license plates found here in Michigan, it was not necessary to multiply the population of the other states by Michigan’s population 49 times.

I ran the correlation between my new variables and frequency for all 49 states and got the following:
                P/D = 89.2% correlation (without top 5 and bottom 5, this is a 90.2% correlation)
                PDIA = 91.7% correlation (stays the same without top 5 and bottom 5)
                PIA = 45% correlation (without top 5 and bottom, this is a 43% correlation)

Summary
It is readily apparent that the most significant factor in sighting out of state license plates is the Population for any given state.  After that, the next most important factor is Distance.  The Per Capita Income Adjusted variable is the weakest variable but should not be entirely ignored.

So, if you want to calculate the difficulty of finding any given state, or predict which states you will see more often than others, simply take the population of all 50 states and divide that by the calculated distance to the other state, and then rank them – the higher the number, the easier that state is to find.  FYI – using the largest city or capital or border statistically will not make any significant difference.  Adding in the adjusted income factor will only give it a slight boost and is more work to find all the per capita incomes for all the states and adjust those based on a COLA. 

Sources –

http://www.missourieconomy.org/indicators/cost_of_living/
http://en.wikipedia.org/wiki/List_of_U.S._states_by_income#States_ranked_by_per_capita_income

Bonus Section – Review of License Plate Apps for iphone
US PL8S
·         List of all 50 states and D.C. with only 1 plate per state
·         List has feature to hide the states that have been found
·         Has Statistics function – Lists what percentage of the 51 States/District you have found (50 States plus D.C.)
·         For the individual states, it lists the date found, how many license plates are issued for the state, and ranks the states into four categories – easy, medium, hard, and very hard

What I like about this app is that it is very simple.  It’s great if you just want to check off each state as you find it.  The information about when and where is also available.

License Plate Zone

·         For all 50 states and D.C., this app lists all the plates issued in that state.  It has a picture of each license plate in that state.  This allows you to check off specifically which plate you found. 
·         In the list of the States, it shows how many different plates are issued for that state.  For example, Alabama has 161 different plates, Alaska has 35 different types of plates, etc.
·         Map feature shows where it was found
·         Lists the date, time, and latitude and longitude of when and where the plate was found.
·         The “Trips” feature lists how many plates from how many different states have been found.  For example, my app currently says I have found 71 plates from 49 different states.
·         Lists all the plates in the order found along with date, time, lat. and long.
·         Allows the same plate from the same state to be selected multiple times if and when that particular plate is found again
·         Can edit the location.  This means that if you are driving, you see a license plate from Alaska, you wait until you are safely parked and enter the information, it will drop a pin of your current location; however, you can move this pin to where you actually saw the license plate.

What I like about this app is that it has all the plates from all the states.  I also like the feature where you can edit where you found the license plate.  I like the fact that it lists the order in which you found them.  It allows a person to enter the same license plate multiple times.  This is the only app that allows a person to do this.

Miles to Go

·         This app like the other apps allows you to track which states you have found. 
·         It has Facts and Quizzes section – this includes capital, largest city, flag, statehood date and order of admission to the Union, nickname, state seal, area and rank, population and rank, state bird and state flower.
·         The quizzes can be customized to focus on just certain aspects of the information in the facts section.  Such as only being quizzed on capitals and largest city versus being quizzed on everything from capitals to state birds.
·         It has a travel log – it is a notes section where you can enter what cities you visited and what you did.
·         This app includes Canada.  Canada has its own section of facts and quizzes.
·         It has a “Progress” chart for the United States and a separate chart for Canada.
·         It’s glitchy.  I cannot reset the game or reset a license plate if I incorrectly enter that after I found a plate and need to fix it.  To reset the entire app, you can delete the app and then reload.  If you just enter an incorrect state, it is impossible to fix.

What I like about this app –
It has Canada!!  The facts and quizzes section looks fun for kids who want to learn some geography and history.  The Notes section is a great travel log.  It is glitchy.  If you want a new game, you can delete the app and then reload it.  If you need to reset a license plate, you are kind of stuck.

States and Pl8S

My least favorite app although it has a few redeeming qualities –
·         It has a running “mileage score”.  The score is based on your location to the center of the other states.  So, if you are in Ohio and you see a Florida license plates you score more “mileage points” for that license plate than if you are in Georgia and you find a Florida license plate. 
·         It has a reminder to not Play and Drive
·         It has a fun facts section for each state.

Summary
The USPL8S app is the simplest to use and great for kids who just want to check off if they found the state or not.

The License Plate Zone app is the one I use the most.  I love the fact that it lists all the plates for each state.  Also, multiple plates from the same state can be logged.  This is the only app that allows a person to do this.

The Miles to Go app is awesome in that it has Canada along with the fun facts and quizzes section.

Then the States and Pl8S has the awesome “Mileage Points” game. 


My ideal app would combine the License Plate Zone features with the Miles to Go features and include Canada and list all the different plates from our northern neighbor.  Then it would also tell you how far you were from that state when you found it.  Fun facts, trivia, and quizzes is an awesome bonus.

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