Texas TTI Visiting Scholarship: Targeting the Bad Emitting Vehicles

We know some vehicles are bad emitters, i.e., they are continuous or intermittent high emitters of one or more priority pollutant. We do not know exact numbers, but we suspect some are poorly engineered vehicles, some are deliberately tampered vehicles and some are incorrectly or unmaintained vehicles [1]. Vehicle Emissions Remote Sensing Systems (VERSSs) provide a measure of across-fleet emissions and have often been used to generate '20% of fleet cause 80% of emissions' headlines [see e.g. 2,3]. However, they give a 'snap-shot' measurement that most likely misassigns both occasional high emissions from otherwise properly functioning emissions systems as bad vehicles, and better measurements from vehicles with failing emissions systems as good vehicles [4]. The unknown scale of such false-negatives and false-positives prevents us from using such techniques to do what we would most like to, namely to reliably target individual vehicles.
Elsewhere, others have already begun to look at alternative techniques, for example both California ARB and Texas COG have instigated work on other passing vehicle emissions monitoring methods like OHMS and PEAQS [5,6]. Both are high-volume active air sampling methods that trade by comparison to VERSSs, reduced fleet capture rates for longer duration but therefore more representative measures of passing vehicle emissions. While these techniques improve confidence, they are still limited by fixed-point deployment, limiting our ability to engine-load profile emissions.
Car-chaser vehicle that include on-board monitors configurated to measure the emissions of other followed vehicles, although out of favour for conventional monitoring activities, could provide us with a better option to target and optimise evidence gathering elements of our efforts to identify and take action against the highest emitting vehicles on our roads. Therefore, the objectives here are two-fold: (1) To explore options to enhance our understanding of high emitters, through the focused analysis of US EPA emission archives, which TTI have access to via established Research Collaboration Agreement. And (2), To repurpose and redeploy conventional in-vehicle emissions measurement systems for car-chaser work focused on the characterisation of followed-vehicle emissions as good or bad, with an aim of scoping the potential for such systems for a role in (near-term) future emissions reduction policy.

References: [1] Ligterink, N., 2017. Real-world Vehicle Emissions. International Transport Forum Discussion Paper 2017-06. [2] Pujadas, M., Dominguez-Saez, A. and De la Fuente, J., 2017. Real-driving emissions of circulating Spanish car fleet in 2015 using RSD Technology. Science of the Total Environment, 576, pp.193-209. [3] Wang, J.M., Jeong, C.H., Zimmerman, N., Healy, R.M., Wang, D.K., Ke, F. and Evans, G.J., 2015. Plume-based analysis of vehicle fleet air pollutant emissions and the contribution from high emitters. Atmospheric Measurement Techniques, 8(8), p.3263. [4] Huang, Y., Organ, B., Zhou, J.L., Surawski, N.C., Hong, G., Chan, E.F. and Yam, Y.S., 2018. Remote sensing of on-road vehicle emissions: Mechanism, applications and a case study from Hong Kong. Atmospheric Environment. 182, 58-74. [5] Bishop, G.A., Hottor-Raguindin, R., Stedman, D.H., McClintock, P., Theobald, E., Johnson, J.D., Lee, D.W., Zietsman, J. and Misra, C., 2015. On-road heavy-duty vehicle emissions monitoring system. Environmental science & technology, 49(3), pp.1639-1645. [6] Smith, J.D., Ham, W., Burnitzki, M., Downey, S., Howard, C., Quiros, D., Hu, S., Chernich, D., Huai. 2018. Quantification of HD in-use Vehicles using the Portable Emissions AcQuisition System (PEAQS). 28th CRC Real World Emissions Workshop March, 18th-21st, 2018, Anaheim, California, US.

Relevance for TTI and ITS: My proposed visit(s) and roll-on work implemented as part of this would allow us to align efforts on related activities at TTI, Leeds and beyond. Work on the analysis of EPA archives could provide a link with Big Data research efforts at TTI and the Leeds Institute of Data Analytics (LIDA, http://lida.leeds.ac.uk/about-lida/). I am already working on ORCS (Open Research Coding Scrum) [13], a Faculty Working Group funded project on data analytics with LIDA, that has an impressive track record developing and commercialising software tools. But, more importantly, the proposed scoping of research into bad emitter vehicles could also provide 'a toe in the water' test of the potential of more significant on-going collaboration, e.g. between TTI's (US Department of Transport funded) Center for Advancing Research in Transportation Emissions, Energy, and Health (CARTEEH https://www.carteeh.org/about/overview/), and the Transport and Health research theme recently instigated at Leeds.
Similarly, work on the development of car-chaser instrumentation could provide earlier proof-of-concept evidence of this collaboration as a hub for instrument development. Such work has the potential to become not just a source of research impact but also an extra revenue-stream. As the UK partner on the parSYNC Research Project, an international collaboration set up to bring smaller, lower cost and energy consumption vehicle emission monitoring systems to market, I led key elements of the development of parSYNC(R), GasMOD(TM) and CA/GE(TM) technologies, including patent-pending work on the parSYNC's unique particulate matter/number (PM/PN) sensory array calibration algorithm, and design of the CA/GE, a highly portable PM/PN calibrator. Resourced, structured and managed correctly, such collaborations can be highly profitable, and I have a track record spotting and developing marketable instruments.

Relevance Outside ITS and TTI: We also need to be looking at how we integrate any TTI/Leeds collaboration with the work of external partners. Alongside such fundamental car-chaser research, we need to also consider the barriers to the technology's use as a legislative tool[E]. This means engaging with government and initiatives like Texas COG's Heavy-Duty Diesel Vehicle Inspection and Maintenance (I/M) Program Advisory Group, which Dr Zietsman collaborated on the establishment of, and Transport Scotland's Emission Data Analysis Partnership (EDAP), which I am involved in, to provide the input and guidance necessary to make such work a viable option for homologation. This work also provides the opportunity to collaborate internationally on work highly relevant to the Living With Environmental Change (LWEC) challenge of making our cities, their infrastructure and surroundings more resilient, sustainable, economically viable and generally better places to live. Better, more independent measures of real-world vehicle emissions will provide policy-makers with the necessary evidence base to drive forward the most effective pollution reduction strategies. Directly relevant research areas include Sustainable Urban Environment, Forecasting Environmental Change, and over-arching EPSRC themes such as Instrumentation, Sensors and Big Data.

Notes: [E] Not properly considering this was a major barrier to the use of remote sensing technologies like RSD and EDAR in 'inspection and maintenance' and regulatory roles and it is likely to be same for car-chaser technology if this is not pro-actively addressed.

References: [13] Ropkins, K., Turner, A., Evans. A. (2016) Open Research Coding Scrum (ORCS). Leeds LIDA Working Group Internal Award, Grant SPTRAN.170011.