If you only need to stay on campus to avoid distractions at home then I'd look into alternate locations to get your afternoon work done. Is there a neighborhood library closer to home or a friendly cafe where you could get your work done? I'd prefer getting most of the commute done in the early afternoon instead of waiting around until 6 in hopes that traffic will ease. If there's an accident or other tie-up you could still end up in heavy traffic - and many drivers would be even more impatient than usual due to the delay.