For the universities, only
上海交通大学 (Shanghai Jiaotong Univ)
西安交通大学 (Xi'an Jiaotong Univ)
北京交通大学 (Beijing Jiaotong Univ)
西南交通大学 (XinanSouthwest Jiaotong Univ, in Sichuan)
国立交通大学 (National Chiao Tung University, in Taiwan)
use pinyin for 交通 because of historical reasons. They all originated from one university, the old 交通大学, where 交通 here comes from an old literature and doesn't simply mean transportation.
Other "交通" universities will use the English translation, either transportation or communication.