C, 35 bytes

f(char*s){while(35^*s++);return*s;}

Same idea as PragmaticProgrammer's answer: find the first #, and output what comes after it -- # for "right", and <space> for "left".

C (loophole), 16 bytes

According to the test cases, it looks like the left road is always exactly one space from the left margin. So...

#define f(s)2[s]