The sentence that is best expanded for meaning is:
"I will be on time unless there is traffic along the way."
This sentence can be expanded to provide more details about the situation, such as the specific circumstances that might cause traffic, the importance of being on time, and how it relates to the overall context. For example:
"I will be on time for the meeting with my clients unless there is heavy traffic along the way due to construction on the main road or an unexpected accident. I’ve been looking forward to this presentation for weeks, and it’s crucial for me to make a good impression."
This expansion adds depth and context to the original sentence.