signal lights

do you ever notice that no 2 signal lights are the same. This is something I noticed as a young boy and never ceases to interest me. do you think that car companies look up the amount of signals per minute (we can call it spm) and ensure that their cars are different. why can't the signals be in unison with each other? it would be nice if I could just once have my signal lights match that of the vehicles around me.