Lag in fetching serial data from Arduino
A couple of things jump out at me:


You only need to run Serial.begin(9600) once in setup() - never in loop() like that.
Your delay(3000) will be causing a 3 second delay when R&gt;L&amp;&amp;R-L&gt;5. 
You don't need to constantly send the data over and over again. You just need to send it once and once only when the state changes.


At the moment you're sending something like:

0000000000000000000000000000000000000000001111111111111111111111111111111111111111111111111111111111111111111111111111111111111100000000000000000000000000000000000000000000000000000000000000000002222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222200000000000000000000000000000000000000000000000000000000000000


when all you really need to do is send 01020. Remember what the state is and only send anything when that state changes from one iteration to the next. And never ever use delay().