Freedom of information response

Rationale behind the signage at transition between 50 mph and 40 mph on Manorway

Publication date: 
Monday 8 April 2024

The transition between the 50 m.p.h. speed limit and the 40 m.p.h. limit on the eastbound carriageway of The Manorway is marked by a single sign. The Road Signs Manual (paragraph 8.2.2 of Chapter 3) generally requires the provision of two signs at a location such as this, one on each side of the road. It goes on to state that any decision to use a single sign should be underpinned by robust risk analysis. Please indicate what analysis was undertaken and provide any other information that casts light on the decisions behind the choice of signage at this point. The relevant speed limit order was introduced in 2017, and so the information that I seek will have been generated in or just before 2017.


The Traffic Signs Manual Chapter 3  (2019) - 8.1.1  states that “the signs must be prescribed by and provided in accordance with TSRGD”

8.2.2 states “There is no specific requirement to provide two terminal signs, one on each side of the carriageway, where the speed limit changes along a length of road. However, in most situations it is recommended that two signs are provided, particularly on motorways and rural dual carriageway roads.”

The Traffic Signs Regulation and General Directions (TSRGD) 2016 gives the Highway Authority Engineers flexibility to be able to assess each site and make a decision specific to each location based on local circumstances.

With regards to the 40 mph speed limit change signage on the Manorway, a secondary upright sign was not installed due to the safety risk the sign would have had presented. The central reservation on this section of the manorway is of insufficient width to accommodate the second 40 mph terminal sign.

A further issue was of concern was that there is a high pressure gas main in the locality which would have prevented excavation and ducting works in order to provide the power needed to illuminate the sign.

Considering the above, it was decided not to install a secondary sign at this location.

In order to help highlight the speed limit change, an alternative sign in the form of a carriageway marking (also an approved sign within the Traffic Signs Regulations) will be introduced.

The Transport Development team are collaborating with other teams to combine works in the area to reduce traffic management costs.

In the meantime, the reduced speed limit remains enforceable with one upright terminal sign.

Request reference:
FOI 13581