One of those galvanized guardians with plenty of room to safely pull off the road. Should be a quick grab for the numbers or anyone working on a streak.
You are looking for a medium size RX Bottle containing only a waterproof log. Permanent markers work best, gel and ballpoint pens work, pencils not so much. The coordinates have been average at least 100 times to within 8'. Your results may vary so a hint is being provided but it is right where you think it is.