title: Effects of raised safety platforms (RSPs) on travel time and traffic delay at roundabouts

authors: Singh, Dharmendra

subjects: Raised Safety Platform

abstract: Raised safety platforms (RSPs) are vertical deflection devices that utilise vertical acceleration to slow vehicle operating speeds down to safe systems-compliant speeds. These devices are not as jarring for drivers as a traditional judder bar and are specifically designed for motorist comfort when traveling at a safe and appropriate speed. RSPs have been specifically identified through the Austroads Guide to Traffic Management and New Zealand Transport Agency (NZTA) Standard Safety Intervention Toolkit as a key safe systems safety intervention.

RSPs are also part of best practice guidance and are designed to slow vehicle speeds enough so that when people make mistakes, they have time to react and avoid a crash. If a crash were still to happen it is kinetic impact energy which determines the severity outcome of a crash is lower. At lower speeds the likelihood of a death or serious injury occurring as a result is drastically reduced.

Safe Systems is a road safety philosophy that requires industry practitioners to provide a more forgiving road system reducing the harm to the human body in the event of a crash. Safe systems have four key pillars safe roads and roadside, safe speeds, safe vehicles, and safe road users. Safe speeds are the areas within which RSPs sit.

Although there are proven safety benefits of RSPs through various literature sources there is still a common user perception that these devices cause a decrease in operational efficiency. Literature is also light on this topic and in cases where past literature is available, they seem to contradict with each other. Some user arguments are that RSPs create congestion at intersections resulting in an increased travel time.

The aim of this thesis report was to provide data-based clarity on the effects of the RSP on travel time and traffic delay at roundabouts to help clarify this area of knowledge gap. This report also seeks to understand effects on traffic speed, crashes, queue lengths, and LOS at roundabouts as a result of RSPs.

This report specifically focuses on roundabouts due to a lack of roundabout-related operational literature as the majority of RSP applications have been at signalised intersections. It should be noted that RSPs are still a new and emerging idea for Australia and New Zealand (NZ). RSPs are a widely used safety intervention in European countries such as the Netherlands.

Investigation in this paper has been done through a review of the literature and quantitative assessment of a sample of sites through microsimulation traffic modeling using Multimodal Traffic Simulation Software. Based on the findings of this paper it is identified that there is a negligible change in traffic delay and a decrease in travel time as a result of RSPs at roundabouts.

The findings of this research shows that RSPs create smoother traffic flow, and safer and better gap selection for vehicles entering a roundabout resulting in improved or the same efficiency for the intersection when compared to pre RSP operation. Some increases in queue lengths was evident on the approach to RSPs and this could relate to driver perception of an increase in congestion. There is no evidence from this paper that supports this as the overall LOS remains unchanged or is improved.

This paper also found that speeds dropped notably on approach to RSPs which resulted in a change in driver psychology where drivers were yielding more at the slower speed. Crash data also showed a decreasing trend in the number of crashes and their severity following RSP installation across all the sites studied. These finding also support past literature on RSP speed and crash reductions.

text: Effects of raised safety platforms (RSPs) on travel time and traffic delay at roundabouts Raised safety platforms (RSPs) are vertical deflection devices that utilise vertical acceleration to slow vehicle operating speeds down to safe systems-compliant speeds. These devices are not as jarring for drivers as a traditional judder bar and are specifically designed for motorist comfort when traveling at a safe and appropriate speed. RSPs have been specifically identified through the Austroads Guide to Traffic Management and New Zealand Transport Agency (NZTA) Standard Safety Intervention Toolkit as a key safe systems safety intervention.

RSPs are also part of best practice guidance and are designed to slow vehicle speeds enough so that when people make mistakes, they have time to react and avoid a crash. If a crash were still to happen it is kinetic impact energy which determines the severity outcome of a crash is lower. At lower speeds the likelihood of a death or serious injury occurring as a result is drastically reduced.

Safe Systems is a road safety philosophy that requires industry practitioners to provide a more forgiving road system reducing the harm to the human body in the event of a crash. Safe systems have four key pillars safe roads and roadside, safe speeds, safe vehicles, and safe road users. Safe speeds are the areas within which RSPs sit.

Although there are proven safety benefits of RSPs through various literature sources there is still a common user perception that these devices cause a decrease in operational efficiency. Literature is also light on this topic and in cases where past literature is available, they seem to contradict with each other. Some user arguments are that RSPs create congestion at intersections resulting in an increased travel time.

The aim of this thesis report was to provide data-based clarity on the effects of the RSP on travel time and traffic delay at roundabouts to help clarify this area of knowledge gap. This report also seeks to understand effects on traffic speed, crashes, queue lengths, and LOS at roundabouts as a result of RSPs.

This report specifically focuses on roundabouts due to a lack of roundabout-related operational literature as the majority of RSP applications have been at signalised intersections. It should be noted that RSPs are still a new and emerging idea for Australia and New Zealand (NZ). RSPs are a widely used safety intervention in European countries such as the Netherlands.

Investigation in this paper has been done through a review of the literature and quantitative assessment of a sample of sites through microsimulation traffic modeling using Multimodal Traffic Simulation Software. Based on the findings of this paper it is identified that there is a negligible change in traffic delay and a decrease in travel time as a result of RSPs at roundabouts.

The findings of this research shows that RSPs create smoother traffic flow, and safer and better gap selection for vehicles entering a roundabout resulting in improved or the same efficiency for the intersection when compared to pre RSP operation. Some increases in queue lengths was evident on the approach to RSPs and this could relate to driver perception of an increase in congestion. There is no evidence from this paper that supports this as the overall LOS remains unchanged or is improved.

This paper also found that speeds dropped notably on approach to RSPs which resulted in a change in driver psychology where drivers were yielding more at the slower speed. Crash data also showed a decreasing trend in the number of crashes and their severity following RSP installation across all the sites studied. These finding also support past literature on RSP speed and crash reductions.

year: 2024

title: Small-scale spatial patterns of Austrovenus stutchburyi in natural and translocated beds

authors: Ross, Frank

subjects: Ecosystem functioning

abstract: Ecosystems are patterned and patchy as a result of spatial and temporal variation in the abundance and distribution of essential resources, as well as due to geological and ecological processes. Large-scale patterns are usually formed by abiotic stressors while small-scale patterns are a result of biotic factors such as inter- and intra-specific interactions. Many suspension feeding bivalves have been reported to form both small and large-scale spatial patterns in soft-sediment environments, in a response to boost resilience from environmental stressors and increase facilitation. However, small-scale spatial patterns of infaunal suspension feeding bivalves are currently not as well studiedfor, despite playing important roles in ecosystem functioning e.g. eutrophication control, resuspend buried nutrients and modify habitats through increased bed roughness. This thesis set out to recognize small-scale spatial patterns of Austrovenus stutchburyi and whether patterns differed with density or environmental properties in Tauranga Harbour. A field survey was used to distinguish small-scale spatial patterns of 
Austrovenus stutchburyi in nine established Austrovenus stutchburyi beds. At each site 
a 4 m² plot was established in a ‘low’, ‘medium’ and ‘high’ density section of Austrovenus stutchburyi aggregates, with core samples taken at 0.5 m intervals within the plots. Austrovenus stutchburyi were then transplanted at low, medium and high densities in 4 m² plots into an area of low ambient densities to observe any spatial pattern formation and environmental effects with density. Austrovenus stutchburyi did not exhibit spatial patterns no different from random in natural beds and was not dependent on density or environmental variables. This was indicated by most of the plots accepting the null hypothesis of Moran’s I which indicates a random distribution. Following the same sampling design as the field survey a translocation experiment was performed to distinguish any small-scale spatial patterns of Austrovenus stutchburyi in a low ambient density environment. Transplanted Austrovenus stutchburyi beds exhibited clustering in high density treatments, indicated by a positive Moran’s I value in all three high density plots (0.335 – 0.420). Both low and medium plots exhibited random patterns, accepting the null hypothesis of Moran’s I. Transplanted Austrovenus stutchburyi beds significantly improved chlorophyll a content with increasing density treatments as chlorophyll a increased by almost a factor of two between ambient and high plots from 11.3 µg g⁻¹ dw to 20.4 µg g⁻¹ dw. However, only a small increase in organic matter content was observed and no modifications were seen towards sediment grain size properties. The results from this study can enrich the knowledge of the currently understudied small-scale patterns of infaunal suspension feeding bivalves including acting as a baseline for future hypotheses and sampling schemes. There is also potential for the high-density translocated plots to act as nursery grounds for reseeded juvenile Austrovenus stutchburyi due to the modified environment becoming nutrient-rich further improving conservation and restoration of estuarine habitats.

text: Small-scale spatial patterns of Austrovenus stutchburyi in natural and translocated beds Ecosystems are patterned and patchy as a result of spatial and temporal variation in the abundance and distribution of essential resources, as well as due to geological and ecological processes. Large-scale patterns are usually formed by abiotic stressors while small-scale patterns are a result of biotic factors such as inter- and intra-specific interactions. Many suspension feeding bivalves have been reported to form both small and large-scale spatial patterns in soft-sediment environments, in a response to boost resilience from environmental stressors and increase facilitation. However, small-scale spatial patterns of infaunal suspension feeding bivalves are currently not as well studiedfor, despite playing important roles in ecosystem functioning e.g. eutrophication control, resuspend buried nutrients and modify habitats through increased bed roughness. This thesis set out to recognize small-scale spatial patterns of Austrovenus stutchburyi and whether patterns differed with density or environmental properties in Tauranga Harbour. A field survey was used to distinguish small-scale spatial patterns of 
Austrovenus stutchburyi in nine established Austrovenus stutchburyi beds. At each site 
a 4 m² plot was established in a ‘low’, ‘medium’ and ‘high’ density section of Austrovenus stutchburyi aggregates, with core samples taken at 0.5 m intervals within the plots. Austrovenus stutchburyi were then transplanted at low, medium and high densities in 4 m² plots into an area of low ambient densities to observe any spatial pattern formation and environmental effects with density. Austrovenus stutchburyi did not exhibit spatial patterns no different from random in natural beds and was not dependent on density or environmental variables. This was indicated by most of the plots accepting the null hypothesis of Moran’s I which indicates a random distribution. Following the same sampling design as the field survey a translocation experiment was performed to distinguish any small-scale spatial patterns of Austrovenus stutchburyi in a low ambient density environment. Transplanted Austrovenus stutchburyi beds exhibited clustering in high density treatments, indicated by a positive Moran’s I value in all three high density plots (0.335 – 0.420). Both low and medium plots exhibited random patterns, accepting the null hypothesis of Moran’s I. Transplanted Austrovenus stutchburyi beds significantly improved chlorophyll a content with increasing density treatments as chlorophyll a increased by almost a factor of two between ambient and high plots from 11.3 µg g⁻¹ dw to 20.4 µg g⁻¹ dw. However, only a small increase in organic matter content was observed and no modifications were seen towards sediment grain size properties. The results from this study can enrich the knowledge of the currently understudied small-scale patterns of infaunal suspension feeding bivalves including acting as a baseline for future hypotheses and sampling schemes. There is also potential for the high-density translocated plots to act as nursery grounds for reseeded juvenile Austrovenus stutchburyi due to the modified environment becoming nutrient-rich further improving conservation and restoration of estuarine habitats.

year: 2020

title: Investigating Māori approaches to trauma informed care

authors: Pihama, Leonie

subjects: Māori health and wellbeing

abstract: This article gives an overview of a three-year Health Research Council funded research project “He Oranga Ngākau: Māori approaches to trauma-informed care”. The study is informed by Kaupapa Māori which provides both the theoretical and methodological foundation for understanding the world, exploring and conceptualising issues. The need for contextualised and culturally safe health and social services is well recognised within Aotearoa and particularly within Mental Health and Addiction Services. While trauma is an experience that can impact on all people, Māori experience trauma in distinct ways that are linked to the experience of colonisation, racism and discrimination, negative stereotyping and subsequent unequal rates of violence, poverty and ill health. Given that Māori are impacted by trauma in specific ways, it is important to explore and identify practice principles that contribute to the development of a framework that supports Māori Providers, counsellors, clinicians and healers in working with Māori. (Authors' abstract).

text: Investigating Māori approaches to trauma informed care This article gives an overview of a three-year Health Research Council funded research project “He Oranga Ngākau: Māori approaches to trauma-informed care”. The study is informed by Kaupapa Māori which provides both the theoretical and methodological foundation for understanding the world, exploring and conceptualising issues. The need for contextualised and culturally safe health and social services is well recognised within Aotearoa and particularly within Mental Health and Addiction Services. While trauma is an experience that can impact on all people, Māori experience trauma in distinct ways that are linked to the experience of colonisation, racism and discrimination, negative stereotyping and subsequent unequal rates of violence, poverty and ill health. Given that Māori are impacted by trauma in specific ways, it is important to explore and identify practice principles that contribute to the development of a framework that supports Māori Providers, counsellors, clinicians and healers in working with Māori. (Authors' abstract).

year: 2017