The answer is the following:
Gerund Phrase: "driving carefully"
Noun Use: Direct Object.
A gerund phrase consists of a gerund, which is an -ing word, as well as other modifiers and/or other objects. They work as nouns, so they can be subjects, subject complements or objects in sentences.
In the example sentence, "She" is the subject, "was able to get past" is the verb, and "the muddy road" is a predicate nominative.