Showing papers by "Margaret Bell published in 2006"

Change-point detection of gaseous and particulate traffic-related pollutants at a roadside location.

Abstract: An 8-year (1998-2005), hourly data set of measurements of NOX, NO2, PM10, PM2.5, and PMcoarse (defined as PM2.5-10) from a busy roadside location in central London has been analyzed to identify important change-points in the time series using a cumulative sum (CUSUM) technique. Randomization methods were used to estimate the uncertainty level associated with the change-points with uncertainty intervals derived using a bootstrap approach. The results show that there is a clear change-point increase for NO2 coinciding with the introduction of the London congestion-charging in February 2003 (95% confidence interval from January-March 2003). At this time there was both an increase in bus numbers and buses fitted with catalyzed diesel particulate filters, which increase direct emissions of NO2. A highly statistically significant change-point was also observed for PMcoarse (95% confidence interval from December 2002-February 2003), which also occurred close to the time of the congestion charge introduction and is most closely related to the increase in bus flows. The increase in PMcoarse at this time has largely compensated for reductions in the concentration of PM2.5, such that the concentration of PM10 has remained almost constant. Comparing the 2 years before and after the introduction of congestion charging, the increment in NO2 above background increased from 22 to 34 ppb and PMcoarse increased from 4 to 9 g m-3. These results could have important implications for meeting European air quality standards that currently set limits for PM10 rather than PM2.5. (A)

Evaluation of a FTIR Emission Measurement System for Legislated Emissions Using a SI Car

Abstract: A series of chassis dynamometer test trials were conducted to assess the performance of a Fourier Transform Infra Red (FTIR) system developed for on-road vehicle exhaust emissions measurements. Trials used a EURO 1 emission compliant SI passenger car which, alongside the FTIR, was instrumented to allow the routine logging of engine speed, road speed, throttle position, air-fuel ratio, air flow and fuel flow in addition to engine, exhaust and catalyst temperatures. The chassis dynamometer facility incorporated an ‘industry standard’ measurement system comprising MEXA7400 gas analyzer and CVS bag sampling which was the ‘benchmark’ for the evaluation of FTIR legislated gas-phase emissions (CO, NOx, THC and CO2) measurements. Initial steady state measurements demonstrated strong correlations for CO, NOx and THC (R2 of 0.99, 0.97 0.99, respectively) and a good correlation for CO2 (R2 = 0.92). Subsequent transient and total mass emissions measurements from replicate samplings of four different driving cycles (two standard cycles, FTP75 and NEDC, and two novel cycles based on real-world data collected in Leeds) also show good response of FTIR and satisfied agreement between the FTIR and CVS bag sampling measurements. In general, the trial results demonstrate that the on-board FTIR emission measurement system provides reliable in-journey emissions data.

Environmental factors in intelligent transport systems

Abstract: Increased car use has highlighted the problem of congestion, not only as a threat to economic growth but also as a substantial contributor to poor air quality, noise, health risk and global warming. This paper draws on the literature to try to heighten the awareness of the issues regarding the environment and health impacts of traffic related pollution. It shows how vehicle technologies and intelligent transport systems can play an important role in addressing environmental problems in urban areas. This review aims to stimulate interest that will hopefully result in a change in perspective so that intelligent transport system implementation is considered, not simply as a tool to reduce delays and lower the risk of accident, but also, through integration of technologies, to deliver good air quality and quieter soundscapes, and thus better quality of life and long-term sustainability of towns and cities.

Study of the Emissions Generated at Intersections for a SI Car under Real World Urban Driving Conditions

Abstract: A precision in-vehicle tail-pipe emission measurement system was installed in a EURO1 emissions compliant SI car and used to investigate the variability in tail-pipe emission generation at an urban traffic junction Exhaust gas and skin temperatures were also measured along the exhaust pipe of the instrumented vehicle, so the thermal characteristics and the efficiency of the catalyst monitored could be included in the analysis Different turning movements (driving patterns) at the priority T-junction were investigated such as straight, left and right turns with and without stops The test car was hot stable running conditions before each test, thereby negating cold start effects To demonstrate the influence of the junction on tail-pipe emissions and fuel consumption, distance based factors were determined that compared the intersection drive-through measurements with steady speed (state) runs Fuel consumption was increased at intersections by a factor of 13~59 CO, THC and NOx emission were increased by a factor of 8~26, 6~21 and 25~10 respectively Benzene emissions were also increased by a factor of 4~21 Through fine-scale analysis of real-world driving profiles and tail-pipe emissions, this research makes a contribution to our understanding of the variability in driving parameters and emission production in urban areas The results of this study will be useful in advising the development of combined traffic/ emission models for urban areas and developing optimal traffic management strategies to minimise emissions

Futures, future urban technologies – undertaking research to enhance sustainability

Abstract: This paper discusses work undertaken in the FUTURES programme; a multi-partner, multi-disciplinary UK-based research activity exploring the role of technology in enhancing the sustainability of urban mobility. A key future challenge will be to use technology to support mobility and access whilst managing traffic levels in a sustainable way. The FUTURES consortium brings together leading UK academics in the field of transport and transport-related technologies and applies an innovative methodological approach to develop new understandings regarding the role of technologies in supporting urban sustainability. This paper explains the FUTURES methodology and discusses some of the early findings from the research. For the covering abstract see E134653.

Utilizing floating vehicle data to improve calibration and validation of traffic micro simulation models

Abstract: There are a growing number of 'floating vehicles', or probes, that are used as mobile sensors to collect up-to-date traffic data across the entire road network. In the UK, GPS based floating vehicle data records collected from large equipped fleets of commercial vehicles, is being used to assess journey times, speeds and congestion across the strategic and urban road networks. In the future, data from factory installed in-vehicle sensors and Advanced Driver Assist Systems is likely to spur further development of dynamic traffic monitoring capabilities, particularly in the study of driver behaviour and the evaluation of Intelligent Transport Systems. This paper aims to review floating vehicle data sources and based on results from a case study, considers the potential use of dynamic traffic information to improve the calibration and validation of traffic microsimulation models. For the covering abstract see E134653.