[Tagging] Barriers near roads

[yarl at o2.pl]

Hi, I want to ask about two types of barrier:

1. noise barrier
(http://commons.wikimedia.org/wiki/File:Ekran-Akustyczny.jpg) - kind
of wall near road, mostly motorway/trunk, sometimes transparent

2. crash barrier
(http://commons.wikimedia.org/wiki/File:CrashBarrier.jpg) - low
barrier from metal or concrete, you can jump over it

IMO 1. should be sth like: barrier=wall + wall=noise_barrier. I don't
know how to tag second one. Any suggestions?

Cheers,
Paweł