traffic lights

[knickknack54]

why do traffic lights have a tube over each light

[stuckin1968]

I may be wrong but I believe it is to prevent strong sunlight obscuring the lights when they are lit.

[Ethel]

Two reasons, depending on the location.

As above, so the lights can be clearly seen even in very bright sunshine but also to stop the lights shining into nearby householders' bedroom windows.

[sigma]

And also to prevent the sun from making them appear illuminated.

[sddsddean]

...and sometimes they have really long hoods (the proper name for the 'tubes'), to stop drivers on other parts of the junction seeing the light and thinking it refers to them.

[Panic Button]

..and to stop tall people licking them, thinking they are sweeties.

[madmondeo]

lol panic

[Compostella]

And to stop people pre-empting the sequence change and getting a head start (which can be too early sometimes)