When you are charged an extra amount for a transportation service, it is called an excess fare. But there are different words that can be used instead of excess fare. For example, overcharge, surcharge, additive price, additional cost, and supplementary fee. These synonyms could be used interchangeably to refer to the additional amount that is paid for a service. It is always important to look out for these synonyms in transportation services to ensure that you are not overcharged or paying an excess fare. Being vigilant will help to prevent being ripped off by unscrupulous service providers who tend to exploit unsuspecting customers.