Adjusting the need for speed: assessment of a visual interface to reduce fuel use.

Previous research has identified that fuel consumption and emissions can be considerably reduced if drivers engage in eco-driving behaviours. However, the literature suggests that individuals struggle to maintain eco-driving behaviours without support. This paper evaluates an in-vehicle visual interface system designed to support eco-driving through recommendations based on both feedforward and feedback information. A simulator study explored participants' fuel usage, driving style, and cognitive workload driving normally, when eco-driving without assistance and when using a visual interface. Improvements in fuel-efficiency were observed for both assisted (8.5%) and unassisted eco-driving (11%), however unassisted eco-driving also induced a significantly greater rating of self-reported effort. In contrast, using the visual interface did not induce the same increase of reported effort compared to everyday driving, but itself did not differ from unassisted driving. Results hold positive implications for the use of feedforward in-vehicle interfaces to improve fuel efficiency. Accordingly, directions are suggested for future research. Practitioner Summary: Results from a simulator study comparing fuel usage from normal driving, engaging in unassisted eco-driving, or using a novel speed advisory interface, designed to reduce fuel use, are presented. Whilst both unassisted and assisted eco-driving reduced fuel use, assisted eco-driving did not induce workload changes, unlike unassisted eco-driving. Abbreviations: CO-2: carbon dioxide; NASA-TLX: NASA task load index; RMS: root-mean-square; MD: mean difference.

How does eco-driving make us feel? Considering the psychological effects of eco-driving.

Despite both the environmental and financial benefits of eco-driving being well known, the psychological impact of engaging in eco-driving behaviours has received less attention within the literature. It was anticipated that being asked to engage in eco-driving behaviours not only has an impact on vehicle fuel usage, but also on the driver, both in terms of their overall mood and willingness to re-engage with the task at a later time. Results from a simulated driving study suggest that although eco-driving was beneficial in reducing fuel consumption, being asked to eco-drive had a negative effect on overall journey time and mood. Engaging in eco-driving did however have a positive effect on self-esteem, suggesting potential longer term psychological benefits of adopting this behaviour.

Use of gene probes to assess the impact and effectiveness of aerobic in situ bioremediation of TCE.

Gene probe hybridization was used to determine distribution and expression of co-metabolic genes at a contaminated site as it underwent in situ methanotrophic bioremediation of trichloroethylene (TCE). The bioremediation strategies tested included a series of air, air:methane, and air:methane:nutrient pulses of the test plot using horizontal injection wells. During the test period, the levels of TCE reduced drastically in almost all test samples. Sediment core samples (n=367) taken from 0 m (surface)-43 m depth were probed for gene coding for methanotrophic soluble methane monooxygenase (sMMO) and heterotrophic toluene dioxygenase (TOD), which are known to co-metabolize TCE. The same sediment samples were also probed for genes coding for methanol dehydrogenase (MDH) (catalyzing the oxidation of methanol to formaldehyde) to assess specifically changes in methylotrophic bacterial populations in the site. Gene hybridization results showed that the frequency of detection of sMMO genes were stimulated approximately 250% following 1% methane:air (v/v) injection. Subsequent injection of 4% methane:air (v/v) resulted in an 85% decline probably due to nutrient limitations, since addition of nutrients (gaseous nitrogen and phosphorus) thereafter caused an increase in the frequency of detection of sMMO genes. Detection of TOD genes declined during the process, and eventually they were non-detectable by the final treatment, suggesting that methanotrophs displaced the TOD gene containing heterotrophs. Active transcription of sMMO and TOD was evidenced by hybridization to mRNA. These analyses combined with results showing the concomitant decline in TCE concentrations, increases in chloride concentration and increases in methanotroph viable counts, provide multiple lines of evidence that TCE remediation was caused specifically by methanotrophs. Our results suggest that sMMO genes are responsible for most, if not all, of the observed biodegradation of TCE. This study demonstrates that the use of nucleic acid analytical methods provided a gene specific assessment of the effects of in situ treatment technologies.