A: Do you want to come in for some tea?
A: 你要不要进来喝个茶呢？
B: No. I'm running late. I really need to hit the road。
B: 不了。我快迟到了， 得上路了。
"running late" 是快迟到了的意思。
"Hit the road" 的 "hit" 有“去”的意思。好比某人每周去健身房三次， 你就可以说 "He hits thegym three times a week."。
"I really need to hit the road." 还可以用说成"I really need to getgoing."。