Hi, I'm going to give you an exemplary letter, use it as reference please ;)
Dear Sir or Madam,
(if you know the name of the person you're writing to, you can mention it with Mr./Mrs./Ms.)
I hope that this letter will find you well. My name is<your name> and I am writing in order to express my deep concern about the scandalous behaviour of rickshaw drivers around <here you go with the name of the place you live in>.
Everybody can clearly see that <here is the place for your first argument, go with something big and obvious, you will get to the details later on, I'm gonna use a random example here, try giving than one ;)> even though, those drivers are an important part of our society, they are not at all considering other vehicles on the road. I have a been a witness to tens of situations where a rickshaw driver forced a car to pull over so it wouldn't run THEM over. <Now we've got a good opportunity to go into the detail and present some data> I checked and only last month, we've had as many as 100 accidents involving rickshaws, it has to speak of something <now, that was grave, it should make our side of the story well heard>.
<Next paragraph is important, because it gives some suggestions for the counter-measures for the problem> Of course, it is not possible for us to completely get rid of the rickshaws, they are an important part of public transportation asfter all. I think though, that they're commuting routes should be separate from the street and regulated. <you can and you should add more suggestions here>
I am looking forward for hearing from you,
Sincerely Yours, <if you know the name of the person you're writing to>
Faithfully Yours, <if you don't know the name of the person you're writing to>
<your name >
That's all, I believe that it should help you well enough :)