What are the helmet and transition rules?

Under the World Triathlon Competition Rules:

• A helmet must be approved by a national accredited testing authority recognised by a World Triathlon member federation, and must be worn whenever you ride the bike in competition, familiarisation and training sessions.
• The helmet must be securely fastened and fit properly at all times. You must not alter it, including the chin strap, or omit any part of it.
• In transition, you must have your helmet securely fastened from the time you take your bike off the rack until you have racked it again after the bike. The strap must stay unfastened in transition while you complete the first segment.
• You may not run with a bike helmet on.
• Marking your position in transition is forbidden. Marks, towels and objects used for marking are removed and you are not told.
• You may not stop in the flow zones of the transition area.
• Wetsuits can only be fully removed in a designated area or at your transition spot. You may undo the upper body and arms before then, provided your torso stays covered.
• Age-group athletes must wear the bib number on the run.