Susan Hughes

Dr Susan Hughes

BSc, DPhil (Oxon)
+44 (0)1483 686618
06 AA 03

Academic and research departments

Department of Civil and Environmental Engineering.


Areas of specialism

Air Quality and Transportation; Numerical Weather Prediction (NWP) and Data Assimilation; Water Quality and Risk Assessments in Developing Countries

University roles and responsibilities

  • NERC SCENARIO Co-Director (
  • CEE PGR Director

Previous roles

2014 - 2017
I was the Departmental lead on the CEE Bronze submission (November 2015) and University panel member on the Institutional Bronze submission (2017/18).


Research interests

Research collaborations

My teaching

Courses I teach on



Completed postgraduate research projects I have supervised

Postgraduate research supervision

My publications


Holloway-Strong M, Hughes SJ (2001) The influence of contact area on the deformation of chalk, QUARTERLY JOURNAL OF ENGINEERING GEOLOGY AND HYDROGEOLOGY 34 pp. 99-110 GEOLOGICAL SOC PUBL HOUSE
Holloway-Strong MU, Hughes SJ, Hellawell EE (2007) Stress-deformation behavior of chalk, International Journal of Geomechanics 7 (6) pp. 403-409
When strong rock masses, with discontinuity patterns parallel and perpendicular to the ground surface, are subjected to normal loads, linear or concave stress-deformation curves are produced. In contrast, chalk rock masses with the same discontinuity pattern, produce convex curves. This paper investigates the underlying mechanisms, which may be responsible for such differences. Experimental results are presented for profiled chalk specimens in which the contact area at the discontinuity boundary is approximately 15% of the specimen cross-sectional area. It was found that these low contact area specimens exhibited both concave and convex behavior. This behavior was attributed to discontinuity closure and yielding of the intact material, respectively. The overall trend in behavior was found to be a function of the contact area at the discontinuity boundary, the initial discontinuity aperture, and the yield stress. © 2007 ASCE.
Mavroulidou M, Hughes SJ, Hellawell EE (2002) A qualitative decision-making tool for transport planners, assessing urban pollution due to traffic, URBAN TRANSPORT VIII 12 pp. 375-383 WIT PRESS
Lim LL, Hughes SJ, Hellawell EE (2005) Integrated decision support system for urban air quality assessment, ENVIRONMENTAL MODELLING & SOFTWARE 20 (7) pp. 947-954 ELSEVIER SCI LTD
Lythe MS, Hughes SJ, Hellawell EE (2001) Long-term countywide NO2 variations in Surrey, AIR POLLUTION IX 10 pp. 559-568 WIT PRESS
Mavroulidou M, Hughes SJ, Hellawell EE (2007) Developing the interaction matrix technique as a tool assessing the impact of traffic on air quality, JOURNAL OF ENVIRONMENTAL MANAGEMENT 84 (4) pp. 513-522 ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Hughes SJ, Hellawell EE, Strongitharm G (2000) Evaluation of traffic related nitrogen dioxide data in Surrey, AIR POLLUTION VIII 8 pp. 359-368 WIT PRESS
Cowan IM, Hellawell EE, Hughes SJ (2001) The relationship between traffic throughput and the associated primary pollutants in Surrey, AIR POLLUTION IX 10 pp. 431-438 WIT PRESS
Canning PE, Hellawell EE, Hughes SJ, Fairhead CJ, Gatersleben BCM (2007) The implementation of the Traffic Management Act in England: the role of technology, URBAN TRANSPORT XIII 96 pp. 381-390 WIT PRESS
Hellawell EE, Lament-Black J, Kemp AC, Hughes SJ (2001) GIS as a tool in geotechnical engineering, PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-GEOTECHNICAL ENGINEERING 149 (2) pp. 85-93 THOMAS TELFORD SERVICES LTD
Wakeling M, Eyre J, Hughes S, Roulstone I (2015) Assimilation of vertical motion from simulated cloudy satellite imagery in an idealized single column model, Quarterly Journal of the Royal Meteorological Society 141 (689) pp. 1198-1207
Satellite infrared sounders are invaluable tools for making observations of the structure of the atmosphere. They provide much of the observational data used to initialize atmospheric models, especially in regions that do not have extensive surface-based observing systems, such as oceans. However, information is lacking in the presence of cloud, as the cloud layer is opaque to infrared radiation. This means that where information is most desired (such as in a developing storm) it is often in the shortest supply. In order to explore the mathematics of assimilating data from cloudy radiances, a study has been performed using an idealized single-column atmospheric model. The model simulates cloud development in an atmosphere with vertical motion, allowing the characteristics of a 2D-Var data assimilation system using a single simulated infrared satellite observation taken multiple times to be studied. The strongly nonlinear nature of cloud formation poses a challenge for variational methods. The adjoint method produces an accurate gradient for the cost function and minimization is achieved using preconditioned conjugate gradients. The conditioning is poor and varies strongly with the atmospheric variables and the cost function has multiple minima, but acceptable results are achieved. The assimilation system is provided with a prior forecast simulated by adding random correlated Gaussian error to the truth. Assimilating observations comparable to those available from current geostationary satellites allows vertical motion to be retrieved with an error of less than a centimetre per second in most conditions. Moreover, evaluating the second derivative of the cost function at the minimum provides an estimate of the uncertainty in the retrieval. This allows atmospheric states that do not provide sufficient information for retrieval of vertical motion to be detected (such as a cloudless atmosphere or a non-moving opaque cloud layer in the upper troposphere). Retrieval is most accurate with upwards motion.
Woods RI, Hughes SJ, Kuras A (1995) Finite element analysis of the effects of rising groundwater on a deep basement, NUMERICAL MODELS IN GEOMECHANICS pp. 657-662 A A BALKEMA
Mavroulidou M, Hughes SJ, Hellawell EE (2004) A qualitative tool combining an interaction matrix and a GIS to map vulnerability to traffic induced air pollution, JOURNAL OF ENVIRONMENTAL MANAGEMENT 70 (4) pp. 283-289 ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Kelay T, Uzzell DL, Gatersleben B, Hughes SJ, Hellawell EE (2001) Integrating scientific and lay accounts of air pollution, AIR POLLUTION IX 10 pp. 23-32 WIT PRESS
Canning PE, Hellawell EE, Hughes SJ, Gatersleben BCM, Fairhead CJ (2010) 'Devolution' of transport powers to Local Government: Impacts of the 2004 Traffic Management Act in England, TRANSPORT POLICY 17 (2) pp. 64-71 ELSEVIER SCI LTD
Grudgings Nick, Hagen-Zanker Alex, Hughes Susan, Gatersleben Birgitta, Woodall Marc, Bryans Will (2018) Why don't more women cycle? An analysis of female and male commuter cycling mode-share in England and Wales, Journal of Transport and Health 10 pp. 272-283 Elsevier
Women are under-represented in commuter cycling in England and Wales. Consequently, women miss out on the health benefits of active commuting over distances where walking is less practical. Similarly, where cycling could replace motorised forms of transport, society is missing out on the wider health benefits associated with reductions in air pollution, road noise and social severance. This paper uses aggregate (ecological) models to investigate the reasons behind the gender gap in cycling. The relative attractiveness of cycling in different areas is described using a set of 17 determinants of commuter cycling mode share: distance, population density, cycle paths, cycle lanes, traffic density, hilliness, temperature, sun, rain, wind, wealth, lower social status, children, green votes, bicycle performance, traffic risk and parking costs. The correlation between these determinants and census-recorded cycling mode share is examined in logit models for commuters who work 2-5 km from home. The models explain a large share of the variation in cycling levels. There are small but significant differences in the importance of individual determinants between men and women. However, the gender gap is largely explained by a differentiated response to the relative attractiveness of an area for cycling, the sum effect of all determinants. The ratio of male to female cycling rates is greatest in areas that are less attractive for cycling, whereas in the most attractive areas the ratio approaches parity. On average, women require a more conducive environment for cycling than men. Since the typical environment in England and Wales is not conducive for cycling, women are under-represented in commuter cycling rates and miss out on the health dividend. The results suggest improvements to the cycling environment may be moderated by the existing attractiveness of the environment for cycling, with improvements in less attractive areas having a smaller absolute effect on cycling rates.
Avini Ramtin, Kumar Prashant, Hughes Susan J. (2019) Wind loading on high-rise buildings and the comfort effects on the occupants, Sustainable Cities and Society 45 pp. 378-394 Elsevier
The design of low to medium-rise buildings is based on quasi-static analysis of wind loading. Such procedures do not fully address issues such as interference from other structures, wind directionality, across-wind response and dynamic effects including acceleration, structural stiffness and damping which influence comfort criteria of the occupants. This paper studies wind loads on a prototype, rectangular cross-section building, 80 m high. Computational Wind Tunnel (CWT) tests were performed using Autodesk Flow Design with the buildings located in London and New York City. The analysis included tests with and without the surrounding structures and manual computation of wind loads provided data for comparison. Comfort criteria (human response to building motion) were assessed from wind-induced horizontal peak accelerations on the top floor. As expected, analytical methods proved conservative, with wind pressures significantly larger than those from the CWT tests. Surrounding structures reduced the mean component of the wind action. As for comfort criteria, across-wind direction governed the horizontal accelerations with wind targeted on the building?s narrow face. CWT tests provide a cheaper alternative to experimental wind tunnel tests and can be used as preliminary design tools to aid civil engineers, architects and designers with high-rise developments in urban environments.
The bicycle is an efficient way to travel. There are individual and population-level health and wellbeing benefits that arise when more people cycle. However, cycling is rare in England and Wales and commuter cyclists are disproportionately likely to be male and middle aged (35 to 49). Society therefore misses out on the wider benefits of higher cycling levels, and women and certain age groups miss out on the individual level benefits.

This thesis uses geospatial analysis to examine cycling behaviours at multiple scales, seeking to understand the interactions between demographics and causal factors of commuter cycling mode share. It also examines the influence of vehicular traffic in detail and considers what actions local authorities might take to increase cycling levels.

Using both aggregate (area-based) and network (route based) modelling approaches, it identifies that the most important factors influencing cycling behaviours are hilliness, traffic, wealth, temperature and population density. Whilst these and other factors differ somewhat in their relative importance between demographic groups, differences in cycling rates are best explained by group-specific responses to the combined influence of all factors ? the relative utility of cycling. On average, women and older (>49) or younger (

Policy should work towards making urban areas compact, dense and traffic free, with vehicle speeds under 30kph and with suitable levels of cycling infrastructure along key corridors to work. Urban form should be designed primarily with female cyclists in mind and male cyclists will benefit accordingly.