Ok. I think that everyone has a good grasp of the sentence in question. A couple of points that coco asked to be pointed out. I think most of them are あたりまえ, but I'll point them out anyways.
向かって走る This is two phrases made up of "to face" and "to run" (or in this case to drive.
Because in English, we don't use multiple verbs in rapid succession like in Japanese, "heading" is I think the best translation as it gives both a direction and a sense of movement, without having to spell out that the subject is driving (although that would be assumed as they are on the highway).
Next, the word 高速道路
There are a number of translations for this like
freeway, highway, interstate, speedway, and expressway.
I think that highway is the most universally understood, as freeway indicates that there are no tolls (Japanese highways are not free), and interstate suggests that you are traveling between states (no states in Japan, only prefectures).
Lastly トイレ. Depending on what country you're from, you're going to call it something diffierent. Loo, toilet, bathroom, restroom, lavatory,john, etc. However, I think that in this case toilet (or restroom) is the best translation, as it is devoid of colloquialism (john, loo) and does not have the connotation of a connecting bath (bathroom). Lavatory sounds too formal, and "I have to go to the lavatory" just doesn't strike me as natural.
Any other comments?
If not, お疲れ様でした。次の文にも頑張りましょう！
Good work, and let's do our best on the next sentence!