(1) Where existing.
In the openings of the median barrier
strip the minimum containment level
can be of lower class than the suggested
minimum one; as to the mobile protections
which allow quick detours of the
traffic on the highways and main
extra urban roads, the lowest containment
level has to be at least of H1. (2) Only for constructions on concrete
(bridges, viaducts,
walls and similar) which have a
lenght more than 10 meters; all
the others are equalized to the
standard side barrier (type b).
The transition from a side barrier
to a border bridge barrier and vice
versa has to happen gradually. The
border bridge is one of the cases
for which it is accepted ASI>1
whithin the limits indicated by
art.6. (3) The choice between two
classes of barriers is made by the
project engineer according to: the
W working width of the chosen barrier,
the geometric features of the road
(kind of transversal section, plane
altimetry, width of median barrier
and so on), the percentage of heavy
traffic (traffic with a mass more
than 3000 Kg) and according to the
relative percentage of accidents.
