A simple laboratory test procedure to accelerate the oxidation of compacted open graded asphalt mix specimens has been developed. It involves heating 100mm diameter by 65mm high cylinders of asphalt at 80 degrees Celcius for 3 days under air pressure of 2070 kPa (300psi). Comparison of the viscosity of the recovered binder with that from field samples of aged OGPA shows that the procedure results in oxidation equivalent to that from about 4.5 years in the field. Compared with untreated specimens, cantabro weight losses were greater by factors of 2.1, 1.9 and 1.5 for laboratory prepared, plant PA14 and plant PA14HS mixes respectively. The highest average mass loss of 25.9 per cent occurred with the laboratory mix. For the plant PA14 and PA 14HS mixes, losses were 4.0 per cent and 13.3 per cent respectively. Measurement of changes in specimen dimensions after the test, and cantabro test results from experiments using 2070 kPa of nitrogen instead of air, show that the high pressures used do not significantly affect the integrity of the specimens. (a)
There has been increasing interest by governments in New Zealand in replacing short car trips (less than 5 kilometress) with trips using other more environmentally friendly modes, such as passenger transport, walking and cycling. However, discussion of the potential for changing short trips often misuses the available data, with the potential cited being based on segments (or legs), which often differ from what most people would consider as a or what we define as a trip chain. The LTSA's 1997/98 New Zealand (Household) Travel Survey database during 2003-2004 has been reformulated to derive chains and tours (beginning and ending at home) to better understand New Zealanders' travel behaviour. Among other things, the research helps to: correct widespread misunderstandings about the nature and frequency of short trips; enable better quantification of potential for change from short car trips to other modes; provide inputs for developing policy and infrastructure programmes, and enable new and improved performance measures. (a)
In order to identify appropriate traffic and loading data for use in road asset maintenance management, other pavement management systems, and for pavement deterioration models, data were collected between 2000 and 2002 from 2,350 randomly selected sites throughout New Zealand and from the four Transit New Zealand weigh-in-motion sites. (a)
Strategic environmental assessment (SEA) is widely used in transport policy development and planning in Europe and North America. It is recognised as a valuable means of analysing and addressing the potential environmental and social impacts of transport policies and plans. To date, experience of SEA in New Zealand has been limited. However, recent changes to New Zealand's transport policy and legislative framework provide the opportunity to develop a more systematic approach to SEA. The introduction of the New Zealand Transport Strategy and the Land Transport Management Act 2003 has enhanced significantly recognition of the environmental and social impacts associated with transport. Importantly, the provisions of the Act also incorporate a number of elements of effective SEA. These include the Act's sustainability focus, its requirements for early and full consideration of alternatives and for early and full opportunities for public participation in land transport planning. (a)
A research project was undertaken in 2001-2003 to investigate the application of employer travel plans in New Zealand. The project's focus was the identification of the most appropriate travel plan method that could be used by New Zealand organisations, and its likely impact on travel modes for the journey to work. Case study employer travel plans were facilitated at two New Zealand organisations as part of this project. The research project involved three main components: a review of international practice and experience with employer travel plans; facilitation of case study employer travel plans at the Auckland Central branch of the New Zealand Police, and the Civic Offices of the Christchurch City Council; and assessment of the results of the employer travel plan case studies. The case studies demonstrated that the standard employer travel plan process can be applied in the New Zealand context. Travel behaviour changes similar to those achieved internationally were observed. (a)
The research, carried out during 2002, has examined the effect of Variable Mandatory Speed Signs (VMSS) on road user behaviour within the Ngauranga Active Traffic Management Scheme (NA TMS), just north of Wellington, New Zealand. The VMSS show speed limits which are considered appropriate during normal (incident free) conditions and reduced speed limits in response to an incident. Speed data was acquired through the use of Automatic Incident Detection (AID) cameras using video imaging processing (VIP). The VMSS are located within the NATMS and are just one component of the dedicated ATMS architecture provided to deal with incidents aimed at reducing delay to road users. The speeds indicated by the VMSS are mandatory and are the only example of such features in New Zealand. Normal speed data and speeds during incidents were recorded over the period January to August 2002. (a)
This study done between July 2003 and June 2004 set out to use relationships between cross-sectional geometry and heavy vehicle performance to estimate the effect of road geometry on heavy vehicle crash risk. It used computer simulation and engineering analyses to determine these effects with three vehicle types: a tractor-semi-trailer, a B-train and a truck-trailer rig. The study found the areas with potential for significant benefits to be: banking in curves, seal width and shoulder treatments, and cross-slope due to camber. The findings should be useful for black spot analysis because the road-geometry features which are likely to influence the risk of particular types of crash are identified. (a)
These Guidelines for integrated stormwater management, prepared in 2003-2004, provide guidance on a range of issues relating to the management of stormwater run-off from state highways and local roads in New Zealand, including: the legal framework within which stormwater management takes place; the management framework (agency responsibilities and management tools); the gaining of resource consents for stormwater management activities; environmental effects and mitigation measures; and best practice engineering methods. In addition to road designers, engineers and managers, the guidelines are for the use of other parties, including roading contractors, resource management agencies (regional councils, territorial local authorities), stormwater asset managers, consultants, iwi, environmental groups, and the general public. (a)
The effects of frost and ice on the skid resistance of a range of road surface types used in New Zealand were examined in a laboratory-based study, carried out in 2001-02. Frost and ice were formed on samples in controlled climate test rooms. In addition the same range of road samples was exposed to natural frost. Road surface types tested included dense and open-graded asphalts, and both fine and coarse textured chipseals. Comparisons were made with actual roads in frost conditions. Fine textured road surfaces were found to be very vulnerable to loss of skid resistance in frost and ice conditions. Coarse textured surfaces appeared to retain more of their skid resistance in frost and ice although the increase in skid resistance is small. The implications for road management are examined. Additional work examined the corrections that should be made to skid resistance results to allow for the effects of very low temperatures on the methods of measurement. (a)
Foamed bitumen stabilisation is gaining wide acceptance internationally for pavement stabilisation, but has not been practised in New Zealand. This report is of a preliminary experimental study, carried out in 2002, to investigate its feasibility and potential applications in this country. Part I presents a review of the literature (up to 2002) on the use of the foamed bitumen process for pavement stabilisation. The review covers topics related to methods of foamed bitumen characterisation, testing methods, engineering properties, design of foamed bitumen mixes, and recent field applications of the stabilisation technique. Part II consists of preliminary experimental work carried out to explore the feasibility of using the technique in New Zealand. The foaming characteristics of two grades of bitumen from two sources currently in use in New Zealand and the resilient moduli of mixes made using a modified AP-20 gradation aggregate are compared. (a)
The accuracy of network survey profiles affects important pavement performance indices such as roughness and rutting. Various international researchers have identified problems with the interaction of road surface macrotexture, sensor footprint size and sample spacing of different types of profiler. Inherent measurement errors are associated with profiler devices and their operation on road surfaces with high levels of macrotexture. This presents difficulties in countries with predominantly chipseal surfaces, such as Australia and New Zealand, when making valid comparisons between profiler systems. The errors caused by large footprint size and high texture interaction have been identified and quantified. Validation criteria addressing these errors have been proposed. Measurement errors in roughness due to tracking or off- line surveying are more influenced by the transverse variability of the pavement condition rather than the transverse position of the survey vehicle. Measurement errors in rutting due to tracking or off line surveying have been quantified in various rutting bands for an idealised survey system that can reproduce the full transverse profile. (a)
A research study was undertaken, in 2002, to facilitate and monitor the effects of a personalised marketing demonstration programme in Birkenhead, Auckland, New Zealand. The research project involved three main components: a review of international practice and experience with personalised marketing; a trial of the preferred personalised marketing approach with a selection of households in Birkenhead, Auckland; and monitoring and evaluation of the Birkenhead trial, based on the results of before- and after-surveys (using travel diaries). The results achieved in the trial were similar to those obtained in other personalised marketing programmes. (a)
The objective of Stage of this research project (carried out in 2002-2003) was to research and identify the most appropriate precast concrete bridge beam shapes that should be adopted in New Zealand as industry standards for the future. This research was considered a priority as the standard bridge beam designs currently used in New Zealand had been adopted as industry standards in the 1970s. These designs are therefore almost 30 years old and out-of-date with respect to design codes, construction techniques, and the higher strength materials now commonly used. A literature survey was made of standard beam usage in Australia, United Kingdom, United States and Canada along with a survey of current New Zealand practice. Following a survey of manufacturers of precast bridge beams, and three consultation workshops, a range of key beam selection criteria were developed that would need to be addressed in any future designs. The recommendation is that full designs for two existing beam shapes (hollow core and I beam) and one new shape (Super-T) are carried out in the second stage of the project. (a)
Corrosion of steel reinforcement is the most serious and common deterioration problem affecting reinforced concrete bridges in New Zealand. Remedial treatments for concrete damaged by corroding reinforcement include electrochemical treatments (cathodic protection, realkalisation and chloride extraction), which potentially offer a permanent treatment, and patch repair, which is cheaper but does not always prevent future deterioration. This research, carried out in 2002-2003, complements a 2001-2002 review of electrochemical treatments. It describes the features of current patch repair techniques, and uses New Zealand and Australian experience to compare the likely long-term performance and costs of both types of treatment for New Zealand bridges. This will enable New Zealand bridge asset managers to select appropriate repair technologies to suit the needs and circumstances of individual structures. The research indicates that immediate costs of patch repair will almost always be lower than the costs of installing electrochemical treatments. Life-cycle costs will also usually be lower for patch repairs, but can favour electrochemical treatments under certain circumstances. (a)
This conference paper, from the 2002 meeting of the Institution of Professional Engineers New Zealand (IPENZ) Transportation Group, reports on research that investigated the use of curve advisory speed signs in New Zealand. After completing a comprehensive literature review on this subject, the author used a series of optical sensors to observe current traffic speed behavior at the site of curve advisory speed signs. The study focused on effectiveness and compliance. Alternative methods for determining curve advisory speeds, using road geometry data or accelerometer/gyro-based systems, were compared with ball-bank surveys. Ball-bank speeds appeared to fit observed mean speeds very well. Road geometry data can provide a reasonable alternative to field survey measures and appears to present no less accurate a method for assessing curve speeds. The author concludes that automated devices for determining curve speeds should be allowed in New Zealand. Driver compliance with the posted advisory speed was 17%, with 10 km/h above the posted speed was 51%, and with the ball-bank speed was 27%. A move to change the existing curve speed criteria to produce more realistic posted speeds would have a potential impact on safety for drivers.
A project, Environmental Protection Measures applied to New Zealand State Highway Roading Projects, was undertaken in 200 1 to review environmental protection measures that have been applied through the Resource Management Act (RMA) process, to a sample of 35 state highway roading projects constructed in New Zealand, between the years 1991 and 2001. The results of the project are presented as two reports. The investigation takes a retrospective look at these projects to find out (using site visits, file searches and interviews with original participants) how the protection measures performed. Volume I is presented in the form of a reference guide to past practice in the management of environmental impacts of roading and contains sections dealing with such issues as sediment control, noise, effects on fish, weed control, landscaping, etc. Volume 2 contains a summary of key issues and observations from the study. This volume provides a focus for areas where further research may be needed and where further improvement could potentially be made to the way that the environmental management of roading projects is currently conducted. (a)
Vehicular traffic on road asphalt generates a variety of inorganic and organic contaminants. These accumulate on the road surface in quantities that depend on the traffic and road conditions. During rainfall events, they are washed from the road surface and make a major contribution to stormwater pollution. This road runoff contains suspended and dissolved inorganic and organic contaminants, and is a problem, particularly in urban areas, because of its potential chronic toxicity for aquatic species in the recipient waterbodies. This project, carried out in 2001, was to investigate contaminants found in New Zealand road runoff and to characterise the components at source. It was also to determine how the relative concentrations, total load and characteristics change with the frequency and intensity of rainfall events. (a)
This project examines the costs and benefits of, and alternatives to, the resource consent process of the Resource Management Act 1991 in circumstances where the process has been applied to routine maintenance works on New Zealand State Highways. The study is based on an historical review of 195 previous consents issued over a five-year period ( 1997 to 2001). The study recommends that future effort be directed at the development of maintenance-friendly regional rules. Alternative methods, including the use of 'region-wide' consents, are not recommended. The total cost of the 195 consents reviewed in the study is estimated to have been $560,000 (an average of $2,900 per consent). These costs appear to have increased over time (by about 30 per cent between 1997 and 2001). The study, carried out in 2001-2002, finds that maintenance works are not always uncontentious. Issues can and do arise through the consent process. Forty-one such issues are reported from previous consents. Some minor environmental benefits resulted. (a)
Three structural asphalt pavements were identified in the Auckland region from which cores were extracted for testing. These cores were taken from the inside wheel track and between the wheel tracks of the left-hand lane. They were tested to assess the changes in properties of the bitumen and asphalt mix with time, and the effects of traffic loading. No significant difference was recorded in results between the core samples extracted from in the wheel tracks compared with those taken from between the wheel tracks. This suggests that traffic has little effect on the properties of the asphalt mix. Viscosity of the recovered binder and the resilient modulus of the asphalt mix both increased with age. Cores from cracked sections of pavement were extracted and the cracks were found to initiate at the surface. The reasons for top-down cracking are discussed. A whole-of-life cost assessment showed that the current Transfund New Zealand project evaluation procedure favours structural asphalt, rather than conventional unbound granular options, for an existing pavement that requires rehabilitation. (a)
Reinforcement corrosion is the most significant durability problem affecting New Zealand concrete bridges. Cathodic protection (CP), chloride extraction and realkalisation are electrochemical treatments that are designed to prevent further deterioration for considerably longer than the typical 10-year repair cycle offered by traditional patch repair techniques. They do not require extensive removal of contaminated but sound concrete. To inform New Zealand bridge asset managers about the potential benefits of these techniques, their technical features are summarised and opportunities and limitations for their use on New Zealand bridges are identified in this report, prepared in 2001 -2002. Case studies of overseas applications similar to possible New Zealand bridge applications are presented, and Australasian designers and suppliers of treatments are listed. Evaluation of data from the case studies and from a literature review suggests that CP offers protection for the remaining life of a structure, although it must be continuously monitored and maintained throughout that time. (a)
