on the front or in the front

[countable, usually singular] (usually the front) the part or side of something that faces forward; the side of something that you look at first
The book has a picture of Rome on the front.

the front [singular] the part of something that is furthest forward
I prefer to travel in the front of the car (= next to the driver).
takie przykłady zdań wraz z zasadami użycia znalazłam http://oald8.oxfordlearnersdictionaries.com/dictionary/front_1

trzeba przyznać,żę dość subtelne są te róznice w zastosowanniu obu form