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Research Report 621 Regulations and safety for electric bicycles and other low-powered vehicles

Published: | Category: Safety, security and public health , Research programme , Research & reports | Audiences: General, Motorists, Walkers & cyclists

This research report presents a review of overseas legislation, technology trends, market and safety analyses for low-powered, low-speed vehicles. These vehicles include electric bicycles, mobility scooters, self-balancing devices and other personal mobility or wheeled recreational devices. Current New Zealand LPV legislation is based only on motor power and how certain LPVs may be used. In all other countries reviewed, top motor-assisted speed is regulated. The report assesses various regulatory and non-regulatory options for improving safety while supporting technological innovation and mode choice options in New Zealand.

Research Report 179 Effects of public transport system changes on mode switching and road traffic levels

Published: | Category: Integrated land use and transport systems , Research programme , Research & reports | Audience: General

A research project was undertaken to appraise international evidence on the effects of changes in urban public transport systems and services on the extent of switching to/from car travel and on total road traffic volumes, and to develop guidelines for use in the evaluation of urban transport projects in New Zealand. The major part of the project involved collection and appraisal of international evidence, for situations where changes have been made to the urban public transport system, on the proportion of additional public transport trips that would otherwise be car driver trips, and on the effects of the mode switching on overall road traffic volumes. Evidence was collected mainly from Europe, USA and Australia and appraised by type of public transport change, ie. major new corridor projects, service enhancements, fare changes and on-road priority projects.

Research Report 502 Assessing pre-tensioned reinforcement corrosion within the New Zealand concrete bridge stock

Published: | Category: Activity management , Research programme , Research & reports | Audience: General

Precast pre-tensioned concrete bridge construction became common in New Zealand in the 1950s and a large number of pre-tensioned concrete bridges were constructed between 1953 and 1980. These bridges do not meet today’s durability requirements and many are at risk of chloride-induced pre-tensioned reinforcement corrosion. This deterioration can be difficult to detect in visual inspections and has immediate structural implications, so prediction or early detection of at-risk structures is critical for bridges to achieve their required service lives. This report presents an assessment of the New Zealand pre-tensioned concrete bridge stock and identifies bridges at risk of pre-tensioned reinforcement corrosion. Construction eras based on evolving construction practices are identified, and examples of typical beam types used in each era are presented. The exposure classification of each pre-tensioned concrete bridge on the state highway network was remotely estimated using a Google Earth-based tool developed for the purpose.

Research Report 006 Geotextiles

Published: | Category: Activity management , Research programme , Research & reports | Audience: General

Geotextiles are permeable textile fabrics used in engineering applications. This report is a review of geotextiles and their uses in pavements of both sealed and unsealed roads. Also reviewed is the use of geotextiles for filtration and sub-surface drainage. Most of the readily available geotextiles are of either woven or non-woven construction using synthetic fibres. The types of synthetic geotextiles and their generalised porperties are described. Specific properties are given for the geotextiles currently available in New Zealand. The test methods used to measure a geotextile's general, mechanical, hydraulic and durability properties are commented on. The four main functions a geotextile can perform are separation, filtration, reinforcement and drainage. The function or funtions a geotextile performs in any specific application depends both on the situation and on the geotextile. Understanding of the function(s) performed in each of the many situations covered is essential for proper geotextile selection and usage.

Research Report 587 Bitumen performance tests

Published: | Audience: General

Aspects of bitumen performance in chipseals related to the development of a New Zealand performance-based specification for chipseal binders were investigated. Compatibility with kerosene: Differences due to the base (unmodified) viscosity were far greater than those produced by small differences in kerosene compatibility showing that this requirement is probably unnecessary in the new specification. Adhesion to aggregate: Acid number and a ‘wetting test’ based on the MSCR test (AASHTO T 350-14) at 25⁰C were suggested for inclusion in the new specification. Such tests provide protection against likely poorly performing bitumens and help ensure batch to batch consistency. The tests would be carried out in conjunction with Vialit plate tests. Chip retention: Bitumen cohesive energy as a control property for chip retention was investigated. The measured cohesive energy is strongly affected by the viscoelastic properties of the binder.

Research Report 110 An alternative to the sand circle test for measuring texture depth

Published: | Category: Activity management , Research programme , Research & reports | Audience: General

The reproducibility and repeatability of the sand circle test for measuring texture depth in pavement surfaces was compared with a new test using wallpaper size and a flexible perspex plate covered by a rubber pad. The new test was found to be more precise. Keywords: sand circle, texture depth, Transit New Zealand stationary laser profilometer, repeatability, reproducibility, alternative test, wallpaper size

Research Report 178 Initial adhesion characteristics of polymer modified binder

Published: | Category: Activity management , Research programme , Research & reports | Audience: General

This report describes work to investigate sealing aggregate bonding to standard and polymer modified bituminous binders. The work included investigation of the variation of adhesion strength for different aggregate surfaces, the effect of water on binder-aggregate bonding, and development of a test for measuring binder spreading rate on plane surfaces. The spreading rate test was generalised to rough surfaces, and results fitted to power law equations for degree of spreading. This test has the potential to become a standard method for evaluating aggregate-binder adhesion, but further work with various aggregate surfaces and comparison with field-trial results is needed to achieve this. Keywords: adhesion, aggregate, bitumen, chipseals, polymer, modified binders, roads, wetting

Research Report 241 Research into traffic peak spreading

Published: | Category: Transport demand management , Research programme , Research & reports | Audience: General

A research study was undertaken, in 2001–02, for New Zealand and in other countries, of the temporal spreading of traffic peaks, or 'peak spreading', on roads in urban areas. The objectives of the study are to:

review available evidence of, and research into, traffic peak spreading obtained from cities in New Zealand and elsewhere
examine the effect of traffic peak spreading on modelling and evaluation. The two major purposes of the report are to:

describe the phenomenon of peak spreading, why it happens, why it is important, and where it has been observed in the world;
assess how peak spreading, given its importance, has been incorporated in new scheme appraisals by various governments and how it has been represented in modelling and evaluation. Recommendations for incorporating peak spreading as an integral part of transport planning are made.

Research Report 308 Environmental impact of industrial by-products in road construction – a literature review

Published: | Category: Environmental impacts of land transport , Research programme , Research & reports | Audience: General

The objectives of this project, undertaken 2005/6, were to:

review the international technical literature on the topic of environmental issues relating to the use of waste and industrial by-products in road construction applications, and
recommend a set of guidelines to allow road controlling authorities and environmental agencies to determine if various waste or environmental by-products are appropriate for use in road construction. The international literature shows that the topic of environmental impact is extremely complex and, by necessity, any assessment strategy needs to be relatively conservative for it to be practical, cost effective and reliable. The study has shown that a number of documents that address the issues of hazardous substances and acceptance criteria for contaminants are currently available in New Zealand. A new assessment process has been suggested as a result of the literature review.

Research Report 372 Resealing strategies to increase seal life and prevent seal layer instability

Published: | Category: Activity management , Research programme , Research & reports | Audience: General

A study of cores from multilayer chipseals shows that fine solid materials (passing 4. 75 mm) fill a significant proportion of the chipseal volume that would otherwise be available for bitumen. If fines are ignored, the available voids are typically about twice the expected volume of bitumen that would be sprayed. Generation of fines may therefore contribute significantly to premature flushing. The origin of these fine materials remains to be examined; at least six different processes may contribute, and the relative contributions may vary from site to site.