。
She was hit by a car while crossing the street.
Literal
She [topic-は] street [object-を] crossing-middle [in-に] car [by-に] was-struck.
車にはねられた is a passive construction — はねる ('to hit/strike,' said of vehicles) in the passive = 'was hit by.' 横断中に ('in the middle of crossing') uses 中 ('during/in the middle of') as a suffix. This adversative passive expresses an unfortunate event that happened to her — a core use of the Japanese passive voice.