Marlborough District Council Roading Assets - Activity Management Plan 2015 - 2018 SECTION 1 EXECUTIVE SUMMARY The expected growth described above needs to be allowed for in the development of financial and physical works FWP’s. 1.6.1.5.2 Increased Demands on the Sealed Network Increased demands come from Traffic Growth, Heavy Commercial Vehicle (HCV) Growth, and increasing Customer Expectations. Demand for Increased Seal Width: increasing traffic volumes place a greater demand on the sealed network with regard to safety and also increase maintenance especially edge break and low shoulder repairs. Council’s Code of Practice for Subdivision and Land Development specifies the desirable seal width for rural roads related to traffic volume. Table 6.1.5.2a shows the desirable seal width and the length of the existing network below the desired width. All urban roads are considered to have adequate width and therefore the demand for seal widening is only on rural roads. Rural Network Desired Seal Length of the Existing % of the Total Traffic AADT Length Width (m) Network Below Desired Sealed Rural (km) Width* Network < 100 217.8 5.0m 91.2 (41.9%) 10.3% 100 to 500 369.9 6.5m 313.3 (84.7%) 35.4% >500 115.8 7.0m 82.2 (71.0%) 11.7% 703.5 Total 486.7 69.2% Desired Seal Widths Rural Roads Table 6.1.5.2a * From RAMM carriageway width table The above analysis shows that, according to seal width data in RAMM, 69.2% of rural roads are below the desired width based on the traffic usage. The length below the desired width has decreased since the last AMP (74% in previous) mainly as a result of widening in association with rehab treatments and updating of the AADT field in RAMM with more accurate AADT data. In order to qualify for financial assistance seal widening need to be economically justifiable as being the least cost maintenance option. In order to produce a list of sites which are likely to meet this criteria, the list of ‘deficient’ sites has been analysed and the following sites removed: Low volume sites (< AADT 100) many of these sites are < 50 AADT; Sites constrained by the physical terrain i.e. Kenepuru Rd, Port Underwood etc. where widening would be expensive and difficult to justify. Most of these sites have already been successfully controlled with a combination of speed restrictions, warning signage and delineation; Sites only marginally below the desired width i.e. < 0.2m, and it is unlikely widening could be justified in these sites; and Sites where widening has already been undertaken but not yet been updated in RAMM. Following removal of the above a total length of 87.0km has been identified for widening, refer Table 6.1.9.1a. Table 6.1.9.1a also includes two sites (i) 8km of Old Renwick Road (R3 Arterial) and (ii) 5km New Renwick Road (R4 collector) which require widening. These sites are currently above the 7.0m minimum width for >500 AADT but with AADT’s approaching 2000 it is considered that a minimum width of 8.5m (state highway control manual recommendation) should be adopted. Previous AMP’s have spread the widening programme over 10 years to meet financial restraints, this approach is considered appropriate. Therefore the seal widening demand is accessed at 87km over the next 10 years or 8.7km per year. Demand for Asphaltic Surfacing: urban surfacing is influenced primarily by the need to minimise noise. The surfacing strategy recognises this and sets maximum chip sizes for chip sealing and some minimum parameters for the use of asphaltic concrete (AC) surfacing. AC is recommended for use in the CBD, it is pedestrian friendly and aesthetically pleasing. Outside of the CBD, AC is recommended in high stress areas because of it resistance to scuffing and on roads with anAADT of >7500. 30 September 2014 Page 37 of Section 1