B430 road on:
[Wikipedia]
[Google]
[Amazon]
B roads are numbered routes in 
Great Britain
Great Britain is an island in the North Atlantic Ocean off the northwest coast of continental Europe. With an area of , it is the largest of the British Isles, the largest European island and the ninth-largest island in the world. It is ...
of lesser importance than A road
A roads may be
*motorways or freeways, usually where the local word for motorway begins with A (for example, ''Autobahn'' in German; ''Autostrada'' in Italian).
* main roads or highways, in a system where roads are graded A, B and sometimes lower c ...
s. See the article Great Britain road numbering scheme for the rationale behind the numbers allocated.
3 digits
4 digits (40xx)
4 digits (41xx)
4 digits (42xx)
4 digits (43xx)
4 digits (44xx)
4 digits (45xx)
4 digits (46xx)
References
{{DEFAULTSORT:B Roads in Zone 4 of the Great Britain Numbering Scheme 4 4