This little road connects Castle Street to St Peter's Street. In 2010, its junction with Castle Street was remodelled to make space for a new guided bus stop. The new arrangement seems to be designed facilitate the movement from Castle Street northbound into Castle Row.
In the City of Cambridge Area A (Consolidation) Order 1993, there are two restrictions on this junction. The first, imposed by article 42 and Schedule 7 Part 1, bans motor vehicles travelling in any direction in Castle Row from proceeding beyond the junction with Castle Street. The second, imposed by article 129 and Schedule 16 Part 1, bans all vehicles from entering Castle Row at its junction with Castle Street from all directions.
Thus, while the road layout at this junction seems designed to encourage cyclists to leave Castle Street here, this move is actually prohibited, unlike the trickier moves out of Castle Row which are permitted.
While we're here, I may as well also mention that the road marking here to diagram 1057 (the bicycle symbol) is only prescribed for use with one of a number of other markings and upright signs (direction 18(1) TSGD), none of which is present.
Oh, and what's this sign doing?
![[cycle] [pedestrian] Madingley Rd ⅓](direction.jpg)
It looks like it might be a variant of diagram 2607 (direction of route to destination shown for pedestrians), but that doesn't allow for adding the cycle symbol. Alternatively, it might be a variant of diagram 2606, but that doesn't allow for changing the colours from white on blue. In either case, the symbols should be on the right-hand side (TSM ch 7 para 7.5) and a distance of ⅓ mile isn't allowed (TSR sch 16 items 5 and 6). I think the right sign should be more like this: