One possible version:

These days, breaking traffic rules and littering are not uncommon, causing serious harm to life and the environment. Changing this situation requires considerable effort on the part of everyone. As for me, it should start on the way to school.

I will keep traffic rules in mind all the way. If I ride a bicycle, Ill always keep to the right and never cross a road until the traffic light turns green. If I walk, Ill never forget to use the pedestrian crossing. Meanwhile, Ill regard it as my duty to help keep our environment clean and healthy. Not only will I keep from littering and spitting anywhere, I will also help clean up the roadside litter whenever possible. I hope my behavior will make a difference.