What does "additional people" mean?

English as a Second Language English Vocabulary, Grammar and Idioms
1

Shuttle Bus is approximately $15 (one person), additional people $2.

So what does “additional people” mean?

TY

2

Shuttle Bus is approximately $15 (one person), additional people $2 。
So what does “additional people” mean?

It seems to me that it costs $15 per person to ride a shuttle bus for a certain number of people in a group (for example, 20 people). The rest of the people in the group will have to pay $2 only.