。
She was so scared she couldn't cross the road.
Literal
She [topic-は] scared [so-て], road [subject-が] was-not-able-to-cross.
Two grammatical points stack neatly here. First, the te-form of an i-adjective (恐くて) is doing cause-and-effect work — 'being scared, [so]...' — exactly parallel to how the で of nouns and na-adjectives (Xで) gives reasons. Second, the potential form 渡れる ('can cross') flips the particle on what looks like the object: the road becomes 道路が, not 道路を, because Japanese routinely re-marks the patient of an ability predicate as a subject. You can think of it as 'the road wasn't crossable [for her].' The kanji 恐い is an older, somewhat literary spelling of what is normally written 怖い today; both read こわい. The 恐 character carries connotations of dread, while 怖 leans toward fright — though in everyday use the distinction has blurred and 怖い is the dominant choice.