======= Vehicle/Fuel Popularity, Ratings, and Growth =======


The Game Mechanics section of the manual details the internal formula used in the game's calculations.  This section of the manual uses pseudo-code and may not be 100% the same as the code in the game. 

The Game Mechanics part of the manual is mainly designed to be a reference for the frequently asked question, "Why do I get this rating when I do X, Y, Z?!" Usually, this answer involves many different variables, which this section of the manual demonstrates. 

**The game mechanics section of the manual shows [[https://idioms.thefreedictionary.com/seeing+how+the+sausage+gets+made|how the sausage gets made]]. So you really may want to avoid this portion of the manual if you enjoy the game.** 


===== Variables =====


^ Name ^ Description ^ ^ Name ^ Description ^
| **GasRate** | The gas rate is a variable that adjusts the fuel prices via the turn events.xml files. | | **Vehicle Type Sales in Region** | These are the total sales of the vehicle type in a region as defined by the city.xml files. In the default maps, these regions are the continents. | 
| **Total Region Sales** | These are the total sales of ALL vehicle types in a region as defined by the city.xml files. In the default maps, these regions are the continents. | | **Current Popularity** | This is the current popularity of the vehicle type in the region. | 
| **VehiclesOfFuelSoldLastYear** | This is the number of vehicles sold last year using this fuel type. | | **TotalVehicleSales** | This is the total number of vehicles sold last year of all fuel types. | 


===== Global Fuel Price =====

Used in conjunction with city fuel rates to calculate the importance of fuel economy and shipping costs.

<code cpp>
gasPrice =  0.0165 * (Year-1900)+ .15;
gasPrice = gasPrice * GasRate;
</code>


===== Vehicle Popularity =====

<code cpp>

Vehicle Type Regional Share = Vehicle Type Sales in Region / Total Region Sales


if(Car Type Sale Share < Current Popularity * 0.85)
    Car Type Regional Popularity = Car Type Regional Popularity * 0.998;
else if(Car Type Sale Share > Current Popularity * 1.15)
    Car Type Regional Popularity = Car Type Regional Popularity * 1.002;
</code>

===== Fuel Popularity =====

<code cpp>
fuelShare = VehiclesOfFuelSoldLastYear / TotalVehicleSales

	
if(fuelShare > 0.35 AND FuelPopularity < 0.35 AND FuelPopularity+0.05 < fuelShare )
{                    
    FuelPopularity = FuelPopularity + 0.05
}

if(FuelPopularity+0.005 < fuelShare )
{                    
    FuelPopularity = FuelPopularity + 0.005
}
else if(FuelPopularity-0.005 > fuelShare )
{                    
    FuelPopularity = FuelPopularity - 0.005
}
</code>