Road User Interactions: Patterns of Road Use and Perception of Driving Risk

The goal of the Road User Interactions research programme is a better understanding of the human factors of our road transport system: road user demographics, risk perceptions of road users, and the driving attitudes of various road user groups. Our analysis of the 1989 and 1999 New Zealand Household Travel Surveys identified several fundamental road user differences and consistent demographic trends over the past 10 years. The driver characteristics of gender, age, and area of residence (urban, secondary urban, and rural) are the demographic factors which most clearly differentiate New Zealand road user groups. Analysis of the patterns of road use suggests that, although these road user groups do drive at distinctly different times, there are periods of conflict which are also associated with the greatest crash risk for these drivers. Our analysis of a sample of road user groups in Hamilton, Auckland, Gisborne, New Plymouth, and Palmerston North found significant differences in their perceptions of risk and driving behaviours. Rural drivers and women drivers rated a range of driving situations as having greater risk than did the other road user groups, and they rated the high risk scenarios as being much riskier. Men indicated the greatest willingness to accept the risk in driving situations and rated their own driving skill as higher. Older drivers also rated driving situations as having higher risk, and young drivers generally rated low risk situations much lower than other drivers. In the survey of driving behaviour, young men in our sample reported very high levels of violations and aggressive violations. The male drivers’ rates of violations and aggressive violations were significantly higher than the women drivers’ and the number of both decreased significantly with age. Finally, inspection of crash data show that young drivers’ and older drivers’ crashes have some characteristics in common; both groups have a disproportionate number of crossing, turning, and manoeuvring crashes at intersections in the mid-afternoon

Influencing driver behaviour through road marking

This paper will describe how road marking can be used to influence driver behaviour in order to improve road safety and traffic flows. Extensive use will be made of examples from recent research undertaken by the authors on overtaking lane design, speed change management, managing speed around curves and improving the safety of high risk sections of roads. This research included both on-road and driving simulator-based measurements. The concept of self explaining roads and what is required to implement it will also be described

The effectiveness of delineation treatments

A literature review undertaken for Transit NZ has found that delineation has a significant effect on driver behaviour with, for example, shoulder rumble strips reducing run-off-theroad crashes by between 22% and 80% (average of 32% for all crashes and 44% for fatal run-of-the-road crashes). The concern that enhancing roadway delineation may sometimes be accompanied by an unwanted increase in drivers’ speeds (known as behavioural adaptation) is not borne out by the research and appears to be a phenomenon associated with a few restricted situations (e.g. where a centre line is added to an otherwise unmarked road). The preponderance of the evidence supports the conclusion that profiled edge lines and centre lines provide drivers with positive guidance and produce significant reductions in crashes as a result of improving drivers’ lateral position. Further, unlike other safety measures that show decreased effectiveness over time due to a novelty effect, profiled lane delineation continues to work regardless of driver familiarity. There is no published research to suggest that profiled edge lines will decrease the effectiveness of a profiled centre line or will result in an increase in crash rates or an increase in the severity of crashes. However it has also been noted that local conditions have a major influence on the level of benefits that can be achieved through improved delineation

The Milky Way halo as a QSO absorption-line system. New results from an HST/STIS absorption-line catalogue of Galactic high-velocity clouds

We use archival UV absorption-line data from HST/STIS to statistically analyse the absorption characteristics of the high-velocity clouds (HVCs) in the Galactic halo towards more than 40 extragalactic background sources. We determine absorption covering fractions of low- and intermediate ions (OI, CII, SiIII, MgII, FeII, SiIII, CIV, and SiIV) in the range fc = 0.20 - 0.70. For detailed analysis we concentrate on SiII absorption components in HVCs, for which we investigate the distribution of column densities, b-values, and radial velocities. Combining information for SiII and MgII, and using a geometrical HVC model we investigate the contribution of HVCs to the absorption cross section of strong MgII absorbers in the local Universe. We estimate that the Galactic HVCs would contribute on average ~52 % to the total strong MgII cross section of the Milky Way, if our Galaxy were to be observed from an exterior vantage point. We further estimate that the mean projected covering fraction of strong MgII absorption in the Milky Way halo and disc from an exterior vantage point is fc(sMgII) = 0.31 for a halo radius of R = 61 kpc. These numbers, together with the observed number density of strong MgII absorbers at low redshift, indicate that the contribution of infalling gas clouds (i.e., HVC analogues) in the halos of Milky Way-type galaxies to the cross section of strong MgII absorbers is <34 %. These findings are in line with the idea that outflowing gas (e.g., produced by galactic winds) in the halos of more actively star-forming galaxies dominate the absorption-cross section of strong MgII absorbers in the local Universe

Research-based Student Selected Components (SSCs)

A presentation on research-based Student Selected Components (SSCs), given at the University of Cambridge on 6-Sept-2023

2.5D Finite Element Simulation – Eddy Current Heat Exchanger Tube Inspection using FEMM

The paper describes the use of the open source electromagnetic finite element software package, FEMM used to simulate heat exchanger eddy current tube inspection. The paper provides an understanding of eddy current impedance plane responses to a number of defects using 2.5D axisymmetric finite element analysis. The scenarios examined are; corrosion, internal and external defects, baffle plate and baffle plate with fretting responses, internal defect, lift-off or improper fit and tube exit responses. A mathematical method of estimating the eddy current density as a function of penetration depth is also investigated with less than 5% over estimation. Finite element mesh optimisation is also investigated and a trade-off is made between accuracy and simulation time. Background knowledge on basic eddy current and heat exchangers is provided in the opening sections of the paper. Probe frequency variation and optimisation along with mesh boundaries are also discussed to help improve the simulation method. The effects of altering inspection frequency and the multiple effects this has on the inspection process are also discussed throughout the paper

Does haste make waste? The human factors of overtaking land design

The aim of this research was to improve overtaking safety and efficiency through improvements in road signage, markings, geometry and speed control associated with the placement and layout of passing lanes. The approach of the research was to explore the effects of several types of overtaking lane treatments in the safety and controlled environment of a state-of-the-art driving simulator. It was found that under the most benign conditions there were no differential effects of the three treatments. With poorer visibility or more taxing road geometry, the drivers relied more heavily on the road markings and signage and the effects of the treatments become more pronounced. The sensitivity to the more "challenging" situations was borne out by the greater speed differential between merge area sections at these sites

Estimation of respiratory rate from motion contaminated photoplethysmography signals incorporating accelerometry.

Estimation of respiratory rate (RR) from photoplethysmography (PPG) signals has important applications in the healthcare sector, from assisting doctors onwards to monitoring patients in their own homes. The problem is still very challenging, particularly during the motion for large segments of data, where results from different methods often do not agree. The authors aim to propose a new technique which performs motion reduction from PPG signals with the help of simultaneous acceleration signals where the PPG and accelerometer sensors need to be embedded in the same sensor unit. This method also reconstructs motion corrupted PPG signals in the Hilbert domain. An auto-regressive (AR) based technique has been used to estimate the RR from reconstructed PPGs. The proposed method has provided promising results for the estimation of RRs and their variations from PPG signals corrupted with motion artefact. The proposed platform is able to contribute to continuous in-hospital and home-based monitoring of patients using PPG signals under various conditions such as rest and motion states

Directivity Investigation of two Annular Phased Array Transducers

Annular phased array transducers are well known in the medical field, with their main use being in ophthalmology and dermatology, and have started to be employed in the NDT industry relatively recently. Annular arrays consist of a centre circular element and multiple ring-shaped elements of different width. This unique geometry of the probe makes it difficult to determine the generating beam of the probe. For this reason, it was decided to produce directivity plots for individual elements for both probe configurations. The directivity plots were produced both experimentally and computationally. The generating knowledge of these plots will be novel for annular arrays since no previous work has been reported in the NDT industry