Do Dogs see reflective jackets differantly?

(poor socialization sounds like to me- Not being in a lot of different surroundings understanding different things. also protecting instincts)

First of all, you have to consider who these people are that your dog is barking at. Anytime your animal is encountering a uniformed individual it is because they are intruding into your property (from your dog's perspective). Be it entering the yard to read your kilowatts consumed, dropping a letter into your mail slot or knocking on the door, this stranger is encroaching on your family's property and space to your dog. Your dog does not know who this person is, they are coming onto his territory and they are doing it for reasons beyond your dog's comprehension. To your dog, they are a potential threat to your safety and a nuisance on his turf. This, of course, upsets and angers your dog enough to bark at him.

But why just people in uniform, you might ask; when the neighbors ring the doorbell, the pooch is as cool as a cucumber. Perhaps it is because most anyone that would come to your home without a uniform on is not a stranger, but is someone that you have specifically introduced him to in a friendly manner. Conversely, anyone in a uniform that would approach your home is not someone you've been able to introduce your pup to, mostly because they are probably someone you would've introduced yourself to, let alone your doggie.

Your dog is barking from the fear and nervousness of a situation they are not familiar with. This sort of anxiety is usually easily aided by training. One thing you can do to get your dog more comfortable with strangers is something called gradual desensitization. What that means is that you are placing him in these unfamiliar situations at a slowly increasing intensity until he is comfortable with even the most intense of these situations. If you don't already walk your dog around the neighborhood, do so and see how he reacts to strangers across the street, strangers approaching on the sidewalk, mail men out in someone else's yard.

You could also take your dog to a busy park with plenty of strangers and engage him in training exercises there. As he gets more and more comfortable as time goes by, be willing to move your training sessions closer and closer to groups of strangers.