Possible Clues:

• A contribution to road safety, one digging up part of the pavement?
• This, by the way, is appropriate behaviour
• Routine procedure for a safe crossing
• Broadcaster's put reins on by stream: safety precaution before crossing
• Cross, having taken these watchful precautions?
• This is advisable, by the way, to avoid getting run down
• This precaution could be taken if on edge, by the way