Simplifying ratio 12:21 gives you 4:7
There are 254,212,610 registered passenger vehicles in the US in 1012 and the population of the US is 313 million. So put in terms of ratio that is about 1:0.8 people/cars
On the bottom of the Cartown game screen there will be a button that says buy cars. Click it. You can buy cars with coins (lowest price: 4,000c). You can also buy cars with your blue points (lowest price: 2 Blue points).
The lowest prices for Freelander cars online is generally approximately twenty thousand dollars. They can be found cheaper used, of course, though.
Cars, usually from the 60's, or early 70's, that have an extreme poswer to weight ratio.
The final gear ratio. Exp. 5th gear
14.7 to 1 is the sweet spot.
For a conventional gasoline engine, the higher the compression ratio, the more efficient the engine. US passenger cars have not had very high compression ratios for about 30 years for multiple reasons. During 1970-1972, Chrysler had the highest compression ratios in US production cars, requiring the highest octane gasoline to operate properly.