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| Chapter 3 – Design considerations and Summary | Page No. |
|---|---|
| 3.1 General | 3 |
| 3.2 Restrictions | 4 |
| 3.3 Development of Design | 4 |
| 3.4 Design detail | 4 |
| 3.5 Summary | 5 |
| Appendix Photographs | 6-8 |
| Chapter 1 - Introduction | Page No. |
|---|---|
| 1.1 Purpose | 2 |
| 1.2 Background Information | 2 |
| 1.3 Existing Highway Layout and Geometry | 2 |
| Chapter 2 – Why the improvement is desirable | Page No. |
|---|---|
| 2.1 General | 2 |
| 2.2 Geometry and visibility | 3 |
| 2.3 Traffic volumes | 3 |
| 2.4 Accidents | 3 |
[1]
The purpose of this document is to support the application for visibility improvement work to be undertaken at the junction of Ballachurry Road and Peel Road, Greeba. It explains the proposal and how it improves the current situation.
The A1 Peel Road is classified as a strategic rural route on the Department’s hierarchy of road networks. It has a 50mph speed limit and it forms part of the TT circuit. Ballachurry Road is a narrow local access road serving 15 properties and a farm. However in addition to the locally generated traffic it is also very popular with motorcycle trail riders, mountain bikers, horse riders and walkers because it leads to and from a greenway track leading to the disused Douglas to Peel railway lines, and Cornelly Mines to the south.
Visibility at the junction onto Peel Road is extremely poor towards the west due to the position of a property known as Hawthorn Cottage and a telegraph pole. Visibility to the east of the junction is even worse because of the proximity of a 7ft high walled garden. Currently motorists cannot emerge from the junction without relying on the two mirrors positioned on the opposite side of the junction. They must edge out very slowly until they can see far enough in each direction to make their decision. This situation is unsatisfactory because it relies on the mirrors being correctly positioned.
The A1 Peel Road is approximately 7.4m wide although there is a pinch point down to 7.2m wide at Hawthorn Cottage. There is a footway on the north side of the road. Ballachurry Road is approximately 6.0m wide with soft verges and no footways.
This chapter highlights the underlying reasons why the improvement is desirable.
The topographical survey of the junction shows that Peel Road is broadly in line with the Department's recommended standard of 7.3m for a 50mph strategic rural route. Ballachurry Road is a typical local rural access road with soft verges. The junction itself is very tight and angular due to the position of Hawthorn Cottage and the telegraph pole. To the east, the radius of the junction is less than 4.0m. When approaching the junction from Peel Road, it is very difficult to locate because of the vegetation and 'hidden' junction. Vehicles often indicate early, and veer across to the centre of the road in order to negotiate the junction because it is so tight.
The visibility from Ballachurry Road to the west (at a distance of 2.4m back from the junction) is barely 4m. Forward visibility to the east is just 6m. Both fall way short of the recommended minimum distance for this type of junction onto a 50mph speed limit.
The latest traffic flow information recorded on Peel Road shows that it carries an average of 8,220 vehicles per day. The 85th %tile speeds of vehicles are 45mph in each direction. There is no information for Ballachurry Road.
There have been no recorded accidents at the junction in the past 5 years.
In developing the design, consideration was given to the following:-
Environmental The design should reflect the rural aspect at the junction and should minimise the impact on the local environment. Any land acquisition should be kept to a minimum.
Technical Although restricted by nearby physical boundary features, the proposals should maximise the land being made available for the visibility splays available in both directions.
Political The local authority has been supportive of the visibility improvement.
[3]
The proposal should be economically viable and fall within the constraints of the Department’s revenue programme.
The design cannot achieve the minimum desirable visibility standards because of neighbouring walls and trees belonging to third party landowners.
For a number of years, the Department has had concerns about the safety of the junction at Ballachurry Road. But any potential junction improvements would have required the acquisition and demolition of Hawthorn Cottage, and the relocation of the garden wall on the opposite side of the junction. Regrettably the cost of acquiring and demolishing the property has not been financially viable so no scheme has ever been progressed.
However the Department has recently been approached by the potential owner of Hawthorn Cottage who has offered the property to the Department for demolition to improve visibility to the west. The removal of the property would also allow a bellmouth to be created to the west, and the telegraph pole would be relocated away from the visibility splay.
The landowner of the walled garden to the east of the junction has agreed in principle to the wall being relocated to improve the visibility to the east. The next landowner to the east of the walled garden has stated that he does not wish the trees forming the boundary to his garden to be removed but he has no objection to them being trimmed back.
With reference to the general layout drawing, Hawthorn Cottage will be demolished thereby improving the forward visibility towards the west from the existing 4m to around 35m. A timber fence will be erected on the highway boundary where Hawthorn Cottage formerly stood.
To the east of the junction the garden wall will be rebuilt on the new visibility line, thus improving the visibility from 6m to around 47m.
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Whilst these proposed visibilities fall below the minimum desirable standards, they maximise the land being made available and would provide much improved visibility in both directions.
The telegraph pole would be relocated outside the visibility splay and the existing traffic mirrors would be retained.
The Department has recently been approached by a potential owner of the Hawthorn Cottage who has offered it to the Department for demolition to improve the visibility to the west of the junction.
Since the offer, the Department has been in discussions with the owner of the walled garden on the opposite side of the junction. He has agreed in principle to alterations to his garden wall to improve visibility towards the east.
Whilst the proposed visibility improvements will not meet the desirable minimum standards, it would offer safer egress from Ballachurry Road onto Peel Road. On completion, the junction will retain its rural appearance with little or no adverse environmental impact. The Department intends to maximise the amount of visibility using land being made available, so the junction improvements are considered to be worthwhile.
[5]
Plate 1 Existing visibility at 2.4m back from the junction towards the west
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Plate 2 Existing visibility at STOP line towards the west Plate 3 Existing visibility at 2.4m back from the junction towards the east
Plate 4 Existing visibility at STOP line towards the east
Plate 5 Existing visibility of Ballachurry Road junction approaching from the east
Plate 6 Existing visibility of Ballachurry Road junction approaching from the west
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