How arbitration works
The following rule holds for a CAN bus:
The "OFF" state (value "0") has  precedence over the "ON" state (value "1"), i.e. with a simultaneous transmission the "1" overwrites the "0". 
 The "0" is dominant, the "1" is recessive.
The following animation illustrates how the so-called non-destructive bitwise arbitration functions:






