You can apply for a traffic officer position at the local or state law enforcement agency that has jurisdiction over the area in which you wish to work. In some cases, this may be a city or county police department, while in others it may be a state highway patrol or department of motor vehicles. To find out where to apply, you can check the websites of local and state law enforcement agencies, or you can visit the employment section of the government website for your state. You can also check job boards and classifieds websites to see if there are any current job postings for traffic officers in your area.