How do i write a letter to object to a motion to vacate a default judgment?

My opponent didn't show up to court on time, so I got a default judgment in my favor. He showed up about an hour after call and asked the judge to vacate the default judgment, claiming he was late because of traffic. I am going to write a letter to object to the motion because I think he should have planned better and that i shouldn't be penalized for it. What kind of content should I include in the letter to make my case? Would the judge even consider granting his request because of his excuse?