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Appendix D - Sight Distance Assessment
Attached to the e-mail Applicant advises of Referral - RAL19/0008.
Technical Note Address: 216 Black Mountain Road Applicant: Murray Richardson 1. Background Tod Consulting were requested to undertake an engineering review of the driveway location(s) for a proposed 2 lot subdivision at 216 Black Mountain Road (lot 9 on RP131369), in support of a Lot Reconfiguration development application to Noosa Shire Council. 2. Assessment of Proposed Driveway A visit to the site revealed that there is an existing driveway that services the existing house on the subject block. This house is to be retained and will ultimately be located within the new lot 1. The site inspection also determined that the location of the existing driveway was also the most appropriate location for the access for both lots due to the steepness of the terrain and the geometry of the road. This means an easement would be required over lot 2 in favour of lot 1 for access purposes. The existing driveway location is shown on the draft plan prepared by Murray and Associates reference 61500. Given this development is in an existing rural residential area and constrained by the existing road geometry, with tighter horizontal or vertical alignments than current design standards, we believe it is appropriate to assess the proposed driveway against the requirements of AS2890.1:2004 – Off Street Car Parking AS2890 states that access driveways are to be located in a manner that provides adequate entering sight distance for traffic exiting the property to view traffic on the frontage road i.e. Black Mountain Road. The driver sight distances are measured, in each direction, from a point 2.5m from the road edge. When checking the sight distances, the driver’s eye height and the height of the object (approaching vehicle) were taken to be 1.15m above the road surface. Black Mountain Road has a posted speed limit of 80kph however give the horizontal and vertical geometry of the road to the west of the access point prevailing speeds are expected to be much less than this (conservatively estimated at 60kph). Notwithstanding, the following assessment has been based on an 80kph speed limit. As outlined in AS2890 for an 80km/hr speed limit a domestic property access requires a sight distance along the frontage road of 95m. When looking left the sight line is measured to the centre of the road. When looking right the sight line is measured to the edge of the frontage road. Tod Consulting have undertaken an inspection of the property and undertaken a physical check of the available sightlines. A summary of the sight distances are tabulated below. 1 16640_43-49 Crescent Road, Eumundi - Technical Note – Revision A
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AS2890.1 – Sight Distance Requirements Sightlines achieved
95m to the left (measured to the centre line) Yes (Refer Photo 1)
95m to the right (measured to the edge line) Yes (Refer Photo 4 & 5)
As detailed above Tod Consulting is confident that compliant sight distances can be achieved in both
directions.
Sightline to the Left
Visibility to the left is unimpeded for a distance exceeding 160m. There is sag in the road approximately
150m from the proposed (existing) access and a bend an additional 120m further on from the sag point.
The available sight distance exceeds the requirements of AS2890 for an 80kph speed limit and would
achieve the requirements for a 100kph speed which is reassuring as the geometry of the road in this
location is likely to result in prevailing speed of vehicles exceeding the 80 kph speed limit.
The photo below shows the visibility available from the access point looking left.
Photo 1 – looking east (left) from proposed access point
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Sightline to the Right
Visibility to the right is constrained by a tight bend approximately 100m west of the proposed (existing)
access point. It is likely that the prevailing speed of vehicles approaching from this direction will be
much less than the posted speed limit of 80kph. Notwithstanding there is still sufficient sight distance
available to achieve the requirements of AS2890 for 80kph.
In the photo below (photo 2) the furthest of three chevron signs is 115m from the access point. The
second photo is taken from the edge of the road at the second chevron sign 105m from the access
point (white car is positioned in the access)
Photo 2 – looking west from proposed access
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Photo 3 – looking east from edge of road 95m from proposed access point
3. Conclusion
Tod Consulting believe that, when assessed against AS2890 for an 80kph speed limit, adequate sight
lines can be achieved in both directions from the proposed driveway.
We present the above findings for your review and request your approval.
Prepared by
Doug Reynolds (RPEQ 9072)
Tod Consulting Pty Ltd
1 August 2018
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