Spoke/wheel reflectors.

[Globalti]

I would agree that in the dark the orange pedal reflectors are probably the best juju.

 

[Mrs M]

And fill their water bottles with fizzy drinks because the gas weighs less than water, no doubt.

Never try this
Mr M put diet coke in my water bottle on holiday. Thought it would be good as a cool drink and to replace energy.
Wrong.
When I opened the bottle for a light refreshment the force nearly blew my head clean off!!
Water or diluting juice only from then on.

 

[Accy cyclist]

Never try this
Mr M put diet coke in my water bottle on holiday. Thought it would be good as a cool drink and to replace energy.
Wrong.
When I opened the bottle for a light refreshment the force nearly blew my head clean off!!
Water or diluting juice only from then on.

And definitely do not put beer in a water bottle! I tried it once in an aluminium bottle with a screw down top. The top blew off after i'd hit a good few bumps. I was left with about a mouthful of beer. i've tried it since with a plastic bottle with the nozzle open to let out the gas. It works but the only trouble is the beer tastes different from a plastic bottle.