Walbran Transport Analysis

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Taihape – Napier Road

The Taihape-Napier Road runs between Taihape township and State Highway 50 at Omahu.  The route is 133.35 km long, 37.3 km of which is unsealed.  The route bisects the largest area of the North Island not served by a State Highway, refer the figure following.  Upgrading, sealing and declaration as a State Highway would result in substantial diversion of existing traffic flows from the alternative State Highway routes (Manawatu Gorge and/or Napier Taupo Road).  The table below summarises the travel distances and travel times of the alternative routes:

Route Distance (km) Travel Time (minutes)
Via Napier-Taupo Road (SH5) 275 195
Via Manawatu Gorge (SH1 &2) 291 190
Taihape-Napier Road 133 120

The route is strategic in nature.  The traffic composition on the Taihape –Napier Road has a very high proportion of heavy vehicles (32% HCVs versus 7% HCVs for “Rural Other” roads in Table A2.1 of Land Transport New Zealand’s Project Evaluation Manual - PEM).  This high proportion of HCVs is evidence to support both the strategic nature of the road and the reputation mentioned below.

The tonnage of freight transported on the Taihape-Napier Road exceeds that transported on any South Island State Highway (except SH1) and also exceeds that transported on several North Island State Highways (source – Transit Research Report 44 “Heavy Transport Routes, Their Identification and Evaluation of a Pilot Route”).

The route is both inter district (connecting Rangitikei and Hastings districts) and inter regional (connecting the Hawke’s Bay and Manawatu-Wanganui regions).
The route has a reputation as a difficult route amongst a significant number of local people and perhaps among those not so local (such as car rental companies and tour operators).  The reputation is probably based on what the road was like some decades ago and may not reflect its current condition and certainly doesn't reflect the condition that the route would be in after the upgrading and sealing is completed.

Figure showing the Taihape – Napier Road
superimposed on the
State Highway network

Many heavy transport operators actively avoid or substantially limit their use of the route due to difficulties they experience on the unsealed section.  Foremost among these difficulties is unloaded trucks getting stuck (ie not getting sufficient traction) and very high tyre wear rates, particularly on the drive axles.  Despite a number of operators continuing to use the route in spite of these problems, larger numbers avoid the route or limit their use of it to loaded journeys (they utilise the Manawatu Gorge or the Napier-Taupo Road for the unloaded return journey) and to trips using very experienced drivers (10 years plus heavy vehicle driving experience).

Consultation with the heavy transport operators, consignors and/or consignees of freight, tourist operators and others has revealed that significant diversion of heavy transport trips from the Manawatu Gorge and/or Napier-Taupo Road to the Taihape-Napier Road will occur if the road is upgraded, sealed and declared a State Highway.  This diversion will ease pressure on the alternative routes, reduce environmental impacts and relocate any remaining environmental impacts away from sensitive receptors.

Upgrading and sealing the route would make a substantial contribution to national transport objectives as set out in the New Zealand Transport Strategy (NZTS) and the Land Transport Management Act (LTMA).  Our report demonstrated that the upgrading, sealing and declaration as a State Highway would be consistent with the nations strategic land transport context.  It raised the question of whether declining the application for upgrading sealing and declaration as a State Highway would be inconsistent with the LTMA and Transit’s stated objectives.

The economic analysis demonstrated that sealing and upgrading would return a BCR of 8.5 ($51.1m benefits) and a FYRR of 63%.  The BCR calculation were conservative, they considered only a small part of the potential diversion catchment, and did not include changes to usage that arising from the changes to the nations international container export ports that are expected, and it assumed that the traffic composition remains unchanged (ie that the road’s reputation is not counteracted).  Including the changes to the nation’s international container ports would increase the BCR to 17.7 ($106.5m benefits).  If the road’s reputation can be overcome a traffic composition similar to that in the PEM can be expected.  This would increase the BCR to 28.6 ($172.1m benefits).  If both these effects occur (and this is not an unrealistic scenario) the BCR would be 45.5 (273.8m benefits).  

Outcome – Still in process

Client comments:

Warwick applies logic from a strategic viewpoint to both challenge and promote arguments supported by sound technical and practical experience.
– David Fraser – Hastings District Council

Of particular note is Warwick’s extensive knowledge of both Land Transport New Zealand and Transit New Zealand policies and objectives. His working relationship with peers within these organisations greatly assists favourable outcomes.
– Barry Strichen – Rangitikei District Council.

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