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: RNAi-mediated Reduction of a Major Ruminant Specific Milk Allergen Using a Transgenic Mouse Model

authors: Jabed, Md Anower

subjects: BLG, miRNA, RNAi, Transgenic mouse, Gene knockdown

abstract: Milk from dairy cows is an important human food. It contains the protein beta-lactoglobulin (BLG) which is not present in human milk and thought to be a major allergen in the milk of cows. RNA interference (RNAi), mediated by sequence-specific micro RNAs (miRNAs), provides a new molecular tool to reduce the levels of undesirable proteins. 

In this study, I have screened ten miRNAs targeting the BLG mRNA for their potential to knockdown BLG expression using a cell-based in vitro assay. I identified four miRNAs which showed substantial bovine BLG (bBLG) (78-97%) and ovine BLG (oBLG) (33-94%) knockdown activity in vitro. Tandem miRNA constructs with combinations of these four single miRNAs did not result in significantly increased knockdown efficiency compared to the respective single miRNA constructs in the in vitro assay (P>0.05). Because targeting of two different regions has the potential for greater knockdown efficiency in vivo, I chose a tandem construct which achieved in vitro up to 99% bBLG knockdown as compared to 92% and 74% of bBLG knockdown by the single miRNAs. The tandem construct also showed 90% of oBLG knockdown in comparison to 92% and 69% of oBLG knockdown by the single miRNAs in the in vitro assay which made it an ideal candidate for the subsequent evaluation in transgenic (Tg) mice. For the in vivo studies, the cytomegalovirus (CMV) promoter of the selected miRNA constructs was replaced with the promoter of the mouse milk protein gene for whey acid protein (WAP) which directs the expression of the BLG-specific miRNAs to the lactating mammary gland. The Tg mouse lines generated with the tissue-specific tandem construct and the single miRNAs used for the tandem miRNA construct were then crossed with an oBLG or bBLG expressing Tg mouse line to generate double transgenic (miRNA-BLG) mice for assessing BLG knockdown in vivo. Analysis of the milk proteins demonstrated that the tandem miRNA reduced the levels of oBLG and bBLG in milk from the miRNA-BLG mice up to 96% and 46%, respectively. This study validates the mammary gland specific expression of miRNAs as a promising approach to knockdown allergenic proteins in milk.

text: RNAi-mediated Reduction of a Major Ruminant Specific Milk Allergen Using a Transgenic Mouse Model Milk from dairy cows is an important human food. It contains the protein beta-lactoglobulin (BLG) which is not present in human milk and thought to be a major allergen in the milk of cows. RNA interference (RNAi), mediated by sequence-specific micro RNAs (miRNAs), provides a new molecular tool to reduce the levels of undesirable proteins. 

In this study, I have screened ten miRNAs targeting the BLG mRNA for their potential to knockdown BLG expression using a cell-based in vitro assay. I identified four miRNAs which showed substantial bovine BLG (bBLG) (78-97%) and ovine BLG (oBLG) (33-94%) knockdown activity in vitro. Tandem miRNA constructs with combinations of these four single miRNAs did not result in significantly increased knockdown efficiency compared to the respective single miRNA constructs in the in vitro assay (P>0.05). Because targeting of two different regions has the potential for greater knockdown efficiency in vivo, I chose a tandem construct which achieved in vitro up to 99% bBLG knockdown as compared to 92% and 74% of bBLG knockdown by the single miRNAs. The tandem construct also showed 90% of oBLG knockdown in comparison to 92% and 69% of oBLG knockdown by the single miRNAs in the in vitro assay which made it an ideal candidate for the subsequent evaluation in transgenic (Tg) mice. For the in vivo studies, the cytomegalovirus (CMV) promoter of the selected miRNA constructs was replaced with the promoter of the mouse milk protein gene for whey acid protein (WAP) which directs the expression of the BLG-specific miRNAs to the lactating mammary gland. The Tg mouse lines generated with the tissue-specific tandem construct and the single miRNAs used for the tandem miRNA construct were then crossed with an oBLG or bBLG expressing Tg mouse line to generate double transgenic (miRNA-BLG) mice for assessing BLG knockdown in vivo. Analysis of the milk proteins demonstrated that the tandem miRNA reduced the levels of oBLG and bBLG in milk from the miRNA-BLG mice up to 96% and 46%, respectively. This study validates the mammary gland specific expression of miRNAs as a promising approach to knockdown allergenic proteins in milk.

year: 2012

title: An indigenous model of career satisfaction: Exploring the role of workplace cultural wellbeing

authors: Haar, Jarrod M.

subjects: career satisfaction

abstract: Despite career satisfaction models being well established, little is understood about the career satisfaction of indigenous employees. Using a sample of 172 Maori employees, the indigenous people of New Zealand, we tested a career satisfaction model with a cultural wellbeing factor over and above established factors of human capital, sociodemographic, individual differences and organizational sponsorship. This new measure workplace cultural wellbeing was found to significantly relate to career satisfaction, accounting for twenty-three percent of the variance over and above the established factors which highlights its importance for indigenous workers. Furthermore, due to collectivistic orientations amongst Maori, collectivism was tested as a potential moderator and found to significantly interact with workplace cultural wellbeing, showing that Maori respondents reported the greatest career satisfaction when workplace cultural wellbeing was high, irrespective of collectivism orientation. This paper offers an extended model for exploring career satisfaction of indigenous workers.

text: An indigenous model of career satisfaction: Exploring the role of workplace cultural wellbeing Despite career satisfaction models being well established, little is understood about the career satisfaction of indigenous employees. Using a sample of 172 Maori employees, the indigenous people of New Zealand, we tested a career satisfaction model with a cultural wellbeing factor over and above established factors of human capital, sociodemographic, individual differences and organizational sponsorship. This new measure workplace cultural wellbeing was found to significantly relate to career satisfaction, accounting for twenty-three percent of the variance over and above the established factors which highlights its importance for indigenous workers. Furthermore, due to collectivistic orientations amongst Maori, collectivism was tested as a potential moderator and found to significantly interact with workplace cultural wellbeing, showing that Maori respondents reported the greatest career satisfaction when workplace cultural wellbeing was high, irrespective of collectivism orientation. This paper offers an extended model for exploring career satisfaction of indigenous workers.

year: 2013