Well, I took the trouble to download your code, then put in my IDE andhit the compile button to get your error messages. Life would be easier if you did those things --> http://arduino.cc/forum/index.php/topic,148850.0.html see the end of section 7.
Your problem is
const int One = 3 , 4;
and lines like that.
How can one constant (or variable for that matter) hold several values? It can not. From your program I can not guess what you meant by that.
if(COUNTER<1Car)is flagged as invalid suffix "Car" on integer constant
Your problem is that you can not combine a number "1" with "Car" like that. I can not guess if you meant 1+Car or a variable named "one_car".
First make some little program that turns LED 1 on if you hit the "add car" and off when you hit the "subtract car". I think that will help you understand some basic syntax of C. After that we can look into the flow of your program logic.