Does a video speed task predict risky speeding behaviour in young and inexperienced drivers?

Vehicle crashes account for the highest number of fatalities for persons aged between 17 and 25 years of age in New Zealand. Despite a myriad of factors precipitating vehicle crashes, excess or inappropriate vehicle speed has been identified as the greatest predictor of crash likelihood and severity. Excess or inappropriate speed reduces a driver’s control over the vehicle, while exaggerating both collision force and the distances required in stopping or safely manoeuvring. One of the major differences identified between young and inexperienced and older more experienced drivers is the ability to adapt driving behaviour to road conditions. Young drivers are more prone to speeding through both a lack of awareness of risks and a desire to seek out novel and stimulating experiences. Recent developments in cognitive models of risk taking propose that older more experienced drivers may adapt their speed by “feeling out” the road conditions, where as young drivers may depend more upon posted limits to determine their speed. A video speed task was developed to measure speed preferences on a selection of road conditions (or ‘environments’) commonly confronting New Zealand motorists. Analyses of speed preferences revealed that young and inexperienced drivers preferred speeds close to the road-limit irrespective of conditions, whereas older and more experienced drivers preferred speeds clearly below the road limit, and demonstrated greater variation in speed preferences on different road environments. This suggests that young and inexperienced drivers both prefer faster speeds and may use the road limit as a target in determining an appropriate speed. Older and more experienced drivers prefer slower speeds, and adapt driving to changing road conditions. Faster preferred speeds were found to be related to a riskier attitudes towards driving in general, and more lenient attitudes toward speeding in particular. In addition, faster preferred speeds were found to be related to a heightened enjoyment of risk taking, as well as the number of speeding convictions issued in the previous 12 months. The used video speed task provided a convenient measure of speeding behaviour in natural driving scenarios, and appeared to be sensitive to differences in the way drivers adjust their behaviour across changing driving conditions. The video speed task might be useful in determining differences in speed choice between day and night time driving scenarios, as well as expanding the road conditions to including wet or foggy driving situations. This may be particularly useful in determining the pre- and post-effectiveness of driver training programs

The effects of road commentary training on novice drivers' visual search behaviour: A preliminary investigation

One of the major challenges facing novice drivers seems to be adequately scanning, detecting, and responding to hazards which present during the course of everyday driving; a process that involves ‘reading the road’ and modifying driver behaviour accordingly. Previous studies have indicated that inexperienced drivers tend to utilise only a small proportion of the visual field when driving, and this limited visual search behaviour may play a significant role in the over-representation of young novice drivers’ involvement in crashes. This deficiency in visual search is especially evidenced through crashes occurring at intersections, or other densely populated road environments. More recently, road commentary has become of interest within a number of driver education initiatives, and several current studies have indicated that road commentary indeed improves drivers’ performance in hazard perception tasks. However, relatively little is known about commentaries influence on the underlying cognitive mechanisms responsible for enhanced situation awareness or hazard awareness, and whether such improvements generalize to a broader range of road scenarios. Using hazard perception and eye-tracking measures, we started to examine how road commentary could influence the way drivers visually accrue and process essential road information. First, our data confirmed that commentary training significantly increased the percentage of hazards identified. But additionally, preliminary eye movement data indicated that road commentary may have influenced visual search behaviour of the participants by ‘prompting’ them to allocate extra visual attention capacity to hazard rich areas, as evidenced by an increase of their fixation clusters across the visual field. This could help increase situation awareness, and convert to safer driving behaviour and reduced risk-taking

The role of hazard perception in speed choice

It is a fact that drivers’ poor speed choices play a significant role in crashes, leading to many fatalities and injuries worldwide (WHO, 2012). Young novice drivers are about twice as likely to be killed in a speed-related crash than older, more experienced drivers (NZTA, 2017). We also know that novice drivers’ hazard perception is often poor and predictive of crash likelihood (Horswill & McKenna, 2004), yet its relationship to their speed choices is virtually unknown. This thesis aimed to fill this critical gap. The first step (Experiment 1) was to examine the ecological validity of a new laboratory-based video speed choice task, which was similar to the task developed by Horswill and McKenna (1999). The speed choices of two gender-balanced groups comprising 24 ‘Novice’ drivers (mean age of 19.3 years) and 24 ‘Experienced’ drivers (mean age of 29.5 years) were recorded. Participants were shown video clips of various urban and rural road situations filmed from a driver’s perspective, and following each clip, asked to select the ‘appropriate’ speed they would feel most comfortable and safe travelling. An eye-tracker (SR-Research II) recorded their eye movements, which allowed for a detailed examination of drivers’ visual search behaviour. Compared to the Experienced drivers, the Novice drivers chose significantly faster overall speeds and adapted their speeds to a lesser degree under the differing road, weather, and lighting conditions. Novice drivers predominantly focused their visual attention immediately ahead of the simulated vehicle, with rapid glances at salient visual features, while the more experienced drivers focused their visual search more broadly and further ahead to include inspection of roadside cues. Road markings were also found to influence drivers’ speed choices, with the presence of clearly defined road-markings associated with higher speed choices. These laboratory-based results were consistent with what would be observed in real driving conditions based on data from naturalistic driving studies, real-world speed choice statistics, and crash data (Turner et al., 2014; Ministry of Transport, 2017). We concluded, therefore, that the speed choice task had considerable ecological validity. In Experiment 2, we replicated the speed choice task conditions of the first experiment but added a separate video-based hazard perception task (Isler, Starkey, & Williamson, 2009), and tested 138 participants, divided into five gender-balanced groups based on age, experience, and licence type (mean age: ‘Learner’= 16.5 years, ‘Restricted’= 18.8 years, and ‘Full (50)’= 57.5 years). Our prediction, based on the reviewed literature (e.g., McKenna, Horswill, and Alexander, 2006), was that more advanced hazard perception skills would facilitate increased awareness of risk, prompting the selection of slower appropriate speeds. The results indicated that both the number of perceived hazards and hazard perception times significantly improved with experience as anticipated. Drivers’ chosen speeds, however, increased with age, with ‘Experienced’ drivers choosing faster speeds than novice drivers (‘Learner and Restricted’) and, to a lesser degree, ‘Full (>50)’, older drivers. This indicated that higher levels of hazard perception skills were often related to choices of faster speeds in the speed choice task, and this finding was unexpected. We concluded that it might be possible that experienced drivers only select slower speeds at the time when they become aware of immediate hazards. This hypothesis required further clarification, forming the basis of the rationale for conducting Experiment 3. In Experiment 3, the same hazard perception task as in the second experiment was merged with the speed choice task to form an experiment measuring speed choices under the immediate influence of hazards. Two groups of participants, 52 ’Novice’ drivers (mean age of 19.9 years) and 37 ‘Experienced’ drivers (mean age of 37.4 years), were asked to select the speed they considered most appropriate immediately following each hazard perception trial. Visual search patterns were recorded using an eye-tracker. This time, longer hazard perception times were associated with choices of faster speeds. Overall, novice drivers showed less efficient visual search strategies when perceiving hazards, requiring about double the number of fixations to identify each hazard, but they also chose faster speeds than their more experienced counterparts. We concluded that if there is a causal relationship between improved hazard perception skills and speed choices, we might reduce drivers chosen speeds in Experiment 4 by improving hazard perception, particularly in novice drivers. Experiment 4 consisted of two studies. In the first study, forty participants were randomly assigned either to a control group or a training group, each composed of twenty drivers ‘Novice’ (mean age of 16.6 years) and ‘Experienced’ drivers (mean age of 31.1 years). Both Novice and Experienced drivers showed significant improvements in hazard perception following road commentary, accompanied by a change in visual focus, compared to the control group. In the second study, we tested the hypothesis that improved hazard perception will lead to slower speed choices. Twenty-two participants, ten ‘Novice’ drivers (mean age of 21.3 years) and twelve ‘Experienced’ drivers (mean age of 29.1 years), were assigned randomly to either a control or test group. We found that immediately following the road commentary, the test group showed significant improvement in hazard perception skills and chose slower speeds compared to the control group. In summary, this thesis revealed several significant new findings and insights, leading to a much better understanding of the underlying factors influencing speed choices of novice and experienced drivers. More efficient hazard perception was clearly related to choices of slower speed when hazards were presented within the speed choice trials, possibly mediated by visual search behaviour. There was strong evidence of a causal relationship when road commentary improved hazard perception and caused drivers to select slower speeds, directly influencing speed choices. Future research could investigate the potential for hazard perception to reduce speed choice in real-world traffic situations, especially for young novice drivers. The knowledge that improving hazard perception can influence safer speed choices is of great value for future road safety initiatives. Such research may be instrumental in the quest to decrease the number of speed-related crashes both in New Zealand and around the world

The Relationship Between Macular Pigment and Visual Performance

This study was designed to assess whether macular pigment optical density (MPOD) is associated with visual performance. One hundred and forty-two young healthy subjects were recruited. Macular pigment optical density and visual performance were assessed by psychophysical tests including best corrected visual acuity (BCVA), mesopic and photopic contrast sensitivity, glare sensitivity, photostress recovery time (PRT). Measures of central visual function, including BCVA and contrast sensitivity, were positively associated with MPOD (p \u3c 0.05, for all). Photostress recovery and glare sensitivity were unrelated to MPOD (p \u3e 0.05). A longitudinal, placebo-controlled and randomized supplementation trial will be required to ascertain whether augmentation of MPOD can influence visual performance

The Relationship Between Macular Pigment and Visual Performance

This study was designed to assess whether macular pigment optical density (MPOD) is associated with visual performance. One hundred and forty-two young healthy subjects were recruited. Macular pigment optical density and visual performance were assessed by psychophysical tests including best corrected visual acuity (BCVA), mesopic and photopic contrast sensitivity, glare sensitivity, photostress recovery time (PRT). Measures of central visual function, including BCVA and contrast sensitivity, were positively associated with MPOD (p \u3c 0.05, for all). Photostress recovery and glare sensitivity were unrelated to MPOD (p \u3e 0.05). A longitudinal, placebo-controlled and randomized supplementation trial will be required to ascertain whether augmentation of MPOD can influence visual performance

A multi-centre, double-blind, placebo-controlled, randomised trial of combination methotrexate and gefitinib versus methotrexate alone to treat tubal ectopic pregnancies (GEM3): trial protocol

Background Tubal ectopic pregnancy (tEP) is the most common life-threatening condition in gynaecology. Treatment options include surgery and medical management. Stable women with tEPs with pre-treatment serum human chorionic gonadotrophin (hCG) levels  1000 IU/L can take significant time to resolve with methotrexate and require multiple outpatient monitoring visits. In pre-clinical studies, we found that tEP implantation sites express high levels of epidermal growth factor receptor. In early-phase trials, we found that combination therapy with gefitinib, an orally active epidermal growth factor receptor antagonist, and methotrexate resolved tEPs without the need for surgery in over 70% of cases, did not cause significant toxicities, and was well tolerated. We describe the protocol of a randomised trial to assess the efficacy of combination gefitinib and methotrexate, versus methotrexate alone, in reducing the need for surgical intervention for tEPs. Methods and analysis We propose to undertake a multi-centre, double-blind, placebo-controlled, randomised trial (around 70 sites across the UK) and recruit 328 women with tEPs (with pre-treatment serum hCG of 1000–5000 IU/L). Women will be randomised in a 1:1 ratio by a secure online system to receive a single dose of intramuscular methotrexate (50 mg/m2) and either oral gefitinib or matched placebo (250 mg) daily for 7 days. Participants and healthcare providers will remain blinded to treatment allocation throughout the trial. The primary outcome is the need for surgical intervention for tEP. Secondary outcomes are the need for further methotrexate treatment, time to resolution of the tEP (serum hCG ≤ 15 IU/L), number of hospital visits associated with treatment (until resolution or scheduled/emergency surgery), and the return of menses by 3 months after resolution. We will also assess adverse events and reactions until day of resolution or surgery, and participant-reported acceptability at 3 months. Discussion A medical intervention that reduces the need for surgery and resolves tEP faster would be a favourable treatment alternative. If effective, we believe that gefitinib and methotrexate could become standard care for stable tEPs

Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis

Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07

Rare coding variants in PLCG2, ABI3, and TREM2 implicate microglial-mediated innate immunity in Alzheimer's disease

We identified rare coding variants associated with Alzheimer’s disease (AD) in a 3-stage case-control study of 85,133 subjects. In stage 1, 34,174 samples were genotyped using a whole-exome microarray. In stage 2, we tested associated variants (P<1×10-4) in 35,962 independent samples using de novo genotyping and imputed genotypes. In stage 3, an additional 14,997 samples were used to test the most significant stage 2 associations (P<5×10-8) using imputed genotypes. We observed 3 novel genome-wide significant (GWS) AD associated non-synonymous variants; a protective variant in PLCG2 (rs72824905/p.P522R, P=5.38×10-10, OR=0.68, MAFcases=0.0059, MAFcontrols=0.0093), a risk variant in ABI3 (rs616338/p.S209F, P=4.56×10-10, OR=1.43, MAFcases=0.011, MAFcontrols=0.008), and a novel GWS variant in TREM2 (rs143332484/p.R62H, P=1.55×10-14, OR=1.67, MAFcases=0.0143, MAFcontrols=0.0089), a known AD susceptibility gene. These protein-coding changes are in genes highly expressed in microglia and highlight an immune-related protein-protein interaction network enriched for previously identified AD risk genes. These genetic findings provide additional evidence that the microglia-mediated innate immune response contributes directly to AD development