A strategic-level modelling tool for evaluating air quality and greenhouse gas mitigation strategies for urban road freight in Sydney

This paper details the development of a strategic-level modelling tool to evaluate the impacts of air quality and greenhouse gas mitigation strategies for urban freight. The model, known as STEAR-F (Strategic Tool for the Environmental Analysis of Road Freight) combines publicly available information on freight travel, fleet characteristics, and emission factors to provide estimates of total Greenhouse Gas (GHG) and non-GHG emissions. Following details of the model development and underlying assumptions, STEAR-F is applied to evaluate strategies currently under consideration in the Sydney region. These include accelerated vehicle scrappage programs, diesel vehicle retrofit programs, Low Emission Zones, alternative fuel programs, and educational/information programs focused on driver behaviour, new technologies and proactive vehicle maintenance

Analysis of a financial incentive to encourage safer driving practices

This paper reports on the behavioural response of motorists to a variable rate charging scheme designed to encourage safer driving practices and reduce exposure to crash-risk – specifically kilometres driven, night-time driving and speeding. The study involved a five-week ‘before’ period of GPS monitoring to establish how motorists drove normally, followed by a five-week ‘after’ period of GPS monitoring in which charges were levied and changes assessed. Incentives were paid to motorists for the difference in the charges between the two five-week periods. Vehicle kilometres travelled (VKT) were reduced by ten percent, although the sample was evenly split by those increasing VKT compared to those decreasing VKT. The proportion of distance speeding fell by 4.7 percent, which when coupled with decreases in VKT, implied a net reduction of kilometres spent speeding of over 40 percent. Three-quarters of the sample reduced their speeding. Exit interviews with a cross-section of participants highlighted the practical difficulties of reducing kilometres, but (more encouragingly) reinforced the potential to reduce speeding

Disaggregate Assessments of Population Exposure to Aircraft Noise

The dual pressures of rapidly growing air passenger and freight traffic and increasing numbers of people living in close proximity to airports and flight-paths is a major social problem in many major urban centres around the world including Sydney. While this impact is manifested through various externalities (e.g., noise, air pollutants, greenhouse gases), it is noise that is the most tangible and complained about issue among affected residents. Current assessments of aircraft noise, involve identification of a ‘typical’ or ‘average’ day of operations, translating this to the total number of events above some specified noise threshold, determining how many people are affected by each event using ABS Census residential population figures (a person-event), and then summing these person-events to derive a total noise load for that airport. While this approach is a convenient way to condense information, we argue it suffers from two serious limitations. First, aircraft operations are in reality highly variable, both within and between days, implying the use of an average does not relate to a person’s perceptions or experiences with noise. Second, the approach implicitly assumes a static population, when in reality people are of course highly mobile. This paper addresses these dual issues using 1) new GIS-based flight movement data to study the noise variability at a highly disaggregate spatial and temporal level of resolution, and 2) a population tracking procedure we have developed to ‘move’ people over the day. We demonstrate, using empirical evidence from Sydney, these procedures lead to markedly different insights about noise impacts, than are discernible under current methods. This in turn has important ramifications for policy-makers planning flight operations and residential settlement patterns in impacted areas

Assessing pedestrian exposure to fine particulates at fine levels of spatio-temporal resolution

A compelling body of international evidence now exists suggesting a causal link between exposure to airborne particulate matter (PM) and adverse health consequences. Travel microenvironments have come under particular scrutiny because PM levels are known to be substantially higher than ambient levels from Fixed Site Monitors (FSMs) on which air quality assessments are based and because people significant proportion of time travelling (e.g., 80 minutes/day in Sydney). Over the last two years, we have developed and tested an approach for assessing the risk of exposure to PM at fine levels of temporal and spatial resolution while travelling by various modes of transport. The approach combines the capabilities of personal Global Positioning System (GPS) technology, portable particle monitors, and voice-recorded information on unusual events, to shed new light on the inherent variability in PM and importantly the location, duration and magnitude of ‘hotspots’. The current paper addresses the critical issue of pedestrian exposure along a busy mixed-use roadway environment in Sydney. We present descriptive and statistical evidence of the key factors impacting overall exposure while walking, the most important of which are general traffic conditions, ambient weather conditions (particularly windspeed), and time-of-day (worse in the morning). We then conduct a ‘hotspot’ analysis in which elevated readings are cross-compared to the information on the tape-recorder. It is clear and striking that particular vehicles (buses, trucks) and events (other pedestrian’s smoking) are highly significant and cannot be ignored if we are to accurately assess and minimise exposure in the future

Missing and inaccurate information from travel surveys: Pilot results

During the implementation of a major regional household travel survey, known as the Victorian Integrated Survey of Travel and Activity 2007 (VISTA07) in Victoria, Australia, a pilot survey was undertaken using GPS to validate the diary survey results, similar to a number of studies in North America and Europe. The pilot results suggest that, as has been reported in most overseas studies, respondents generally underreport their travel significantly. Further, it is also found that respondents tend to overestimate trip times and underestimate (seriously) the distance of their travel. It is also noted that there are a significant number of respondents whose reporting is quite accurate, whilst a minority report significantly different information from what the GPS measures. However, a result found in this study that has not been reported before is that there is a very significant difference between the accuracy of reports from those asked to carry a GPS and those who were not asked to do so. This result suggests that the levels of underreporting of travel found in previous studies may be underestimated to a greater extent than previously believed particularly when one considers that VISTA07 uses a face-to-face recruitment methodology. It must be noted, however, that this was a pilot survey and that the sample size is too small to generalise the conclusions, which should not be used to scale any VISTA07 results

Development of a kilometre-based rewards system to encourage safer driving practices

There is growing interest in using kilometre-based financial mechanisms to encourage safer driving practices and reduce accident claims. The rationale behind such an approach is that in addition to driver characteristics such as age and gender, crash risk is intrinsically a function of both the kilometres driven and the circumstances under which those kilometres are driven (time-of-day, day-of-week, road type, speeding etc). In this paper, we explore options for designing a kilometre-based rewards scheme that incentivises drivers to reduce their kilometres, night-time driving and speeding using recent accident data and travel survey data collected in the Sydney Greater Metropolitan Area (GMA). Results show that young drivers (17-30 year-olds) would be hardest hit by the proposed scheme with middle-aged drivers (31-65) faring the best. The impacts of the reward system are then assessed hypothetically using evidence from 125 motorists who have completed five weeks of driving in which their kilometres, night-time driving and speeds are monitored using the latest GPS technology. Various charging scenarios and hypothesised behavioural changes are implemented to assess both their incentive for change and the overall financial impact for the project. These results are used in conjunction with the theoretical and empirical justification outlined in this paper, to set the final charging regime rates based on the overall study budget

Daytime Population Tracking for Planning and Pollution Exposure Assessment

Knowing more precisely where people are across the day and when they are there is fundamental information for many fields including transportation planning, environmental impact analysis, marketing and emergency evacuation. In this paper, we adapt a methodology originally proposed by Roddis and Richardson (1998) for tracking populations across the day using large household travel survey databases. Using five-year pooled data from the Sydney HTS, we effectively take population ‘snapshots’ of the city every 5 minutes, and locate the population using the origin-destination, time and weighting information from the survey sample. We then apply the approach to two different case studies, namely 1) emergency evacuation in the Sydney CBD, and 2) environmental exposure to noise pollution. Through the case studies we demonstrate the various strengths of the approach as well as the caveats, which primarily relate to sample size issues for small-area applications, our ability to rely on people to accurately record where they go, and the frequent need to examine weekday and weekend populations separately. In the case of environmental exposure, we need to understand the production and dispersion behavior of the various pollutant types, if we wish to understand a ‘dynamic’ population exposure to each of these pollutants more precisely

Predicting fine particulate concentrations near a busy intersection in Sydney using artificial neural networks

Scientific evidence of the connection between vehicle emissions and public health outcomes continues to grow. Key to this connection is the accurate monitoring and prediction of pollution concentrations within transport microenvironments at fine levels of spatial and temporal disaggregation. This paper explores the potential for using Artificial Neural Networks for such a purpose, focusing on temporallydisaggregate prediction of PM2.5 concentrations for a busy intersection in Sydney. The main findings are that with knowledge of ambient PM2.5 concentrations, traffic volumes and weather conditions, the approach is able to explain over 90 percent of the variation in PM2.5 concentrations at the intersection, and over 70 percent of the variation when applied to an independent data set collected at the same location

An empirical assessment of the feasibility of battery electric vehicles for day-to-day driving

Driven by sustainability objectives, Australia like many nations in the developed world, is considering the option of battery electric vehicles (BEVs) as an alternative to conventional internal combustion engine vehicles (ICEVs). In addition to issues of capital and running costs, crucial questions remain over the specifications of such vehicles, particularly the required driving range, recharge time, re-charging infrastructure, performance, and other attributes that will be of importance to consumers. With this in mind, this paper assesses (hypothetically) the extent to which current car travel needs could be met by BEVs for a sample of motorists in Sydney assuming a home-based charging set-up, which is likely to be the primary option for early adopters of the technology. The approach uses five weeks of driving data recorded by GPS technology and builds up home-home tours to assess the distances between (in effect) charging possibilities. An energy consumption model based on characteristics of the vehicle, and the speeds recorded by the GPS is adapted to determine the charge used, while a battery recharge model is used to determine charging times based on the current battery level. Among the most pertinent findings are that over the five weeks, i) BEVs with a range as low as 60km and a simple home-charge set-up would be able to accommodate well over 90% of day-to-day driving, ii) however the incidence of running out of charge increases markedly for vehicles below 24 kWh (170 km range), iii) recharge time in itself has little impact on the feasibility of BEVs because vehicles spend the majority of their time parked and iv) while unsuitable for long, high-speed journeys without some external re-charging options, BEVs appear particularly suited for the majority of day-to-day city driving where average journey speeds of 34 km/h are close to optimal in terms of maximising vehicle range

Variability of Personal Exposure to Fine Particulates for Urban Commuters inside an Automobile

Over the last decade, a growing body of evidence has emerged to suggest a causal link between short-duration exposure to elevated levels of fine airborne particulate matter and adverse health consequences. It is believed much of this ‘peak’ exposure occurs in transport microenvironments both because of the higher levels of fine particulates associated with road traffic, primarily from diesel exhaust emissions, and the fact people spend a significant amount of time traveling (for instance, 80 minutes/day for residents of Sydney). While previous studies have suggested substantial differences in exposure rates due to factors such as choice of mode, route, in-vehicle conditions, and meteorological factors, current measurement techniques have restricted insights to fairly coarse sampling intervals (e.g., every half hour, every trip). As a consequence, little tangible evidence is available on how pollution varies over a trip and most critically about the location, duration, and magnitude of peak excursions within trips. The current paper reports on a study in which the capabilities of Global Positioning Systems (GPS) and real-time particle monitors are combined to address this problem for an urban commute trip in Sydney. This ability to precisely spatially reference pollution data and in particular identify ‘hotspots’ holds considerable promise for both our understanding and reporting of such data in the future