Light barrier

[kenjiro-san]

Hello,
I'd like to ask you about an expression I found in the text about automatic road tolling system. Here's the sentence:
"This solution is installed adjacent to the lane and requires no in-road equipment or light barriers."
What do they mean by light barriers? Traditional traffic lights (ex. red, yellow, green) or something else?

<<Second question deleted.>>

Thanks a lot!

 

[owlman5]

I wonder if your text is using "light barriers" to mean "barriers built of light material"? I can't tell from the context. It might also be using "light barriers" with the meaning "barriers with lights on them". I can't see any reason to believe that the text is referring to ordinary traffic lights.

 

[kenjiro-san]

That's exactly what I found confusing here. Light or light? But in this case I'd guess they mean traffic lights - perhaps not so ordinary, but ex. a red/off or red/flashing yellow system. Thanks anyway!

 

[Keith Bradford]

I have come across the term "light barrier" to mean an infra-red or similar beam which hits a sensitive cell. When someone passes through the beam, a circuit is broken, triggering an alarm, or adding to a count, or halting dangerous machinery, etc.

 

[kenjiro-san]

Thanks, Keith, I guess this one fits best.