Developing a 'Road Safety Desert' Methodology for South Africa

Newlands, Alexandra

Developing a 'Road Safety Desert' Methodology for South Africa

Thesis / Dissertation

2023

Abstract

Road safety is a significant problem in today's world, with the number of fatalities caused by road traffic crashes rising every year. The road safety problem has been described as ‘an epidemic on wheels' (Lamont, 2010), which is substantiated by the fact that over 1.35 million people die each year on the world's roads (WHO, 2018a). South Africa's road fatality rate – 21.3 deaths per 100 000 population (RTMC, 2019; STATSSA, 2019) – is considerably higher than the global rate of 18.2 deaths per 100 000 population, and is one of the highest in Africa and the world (WHO, 2018a). Although South Africa's road fatality rate has continued to decrease over the last decade, the current rate is still unacceptably high. An average of 34 road fatalities occur each day, with 40.5% of all fatalities being some of the most vulnerable road users – pedestrians (RTMC, 2019). Additionally, road crashes cost the country's economy approximately R143 billion in total per year (Labuschagne et al., 2016). Drastic change needs to occur, in order to save the economy billions of Rands, and, more importantly, thousands of lives. In order to understand and improve the road safety situation of a region and thus decrease the number of road traffic crashes and fatalities, effective road safety assessments must be carried out. While the current road assessment methodologies (e.g., hotspot analyses, fatality rates) provide informative and useful information about the state of road safety in a region, none of them have been able to make a radical difference in solving the road safety problem in the South African context. This indicates that current assessment methodologies are not sufficient for combatting the high fatality rate and do not provide adequate data for tackling this significant problem. The lack of sufficient road safety assessment methodologies has led to the development of a new road safety assessment approach– namely ‘road safety deserts'. This new methodology makes use of the ‘desert concept', which is a concept that assesses the equitable distribution of goods and services. In academic literature, a ‘desert' is based on a comparison of supply and demand, which was first used to assess access to nutritious food. ‘Food deserts' are defined as “those areas of cities where cheap, nutritious food is virtually unobtainable” (Clarke et al., 2002; Whelan et al., 2002; Wrigley et al., 2002). ‘Transit deserts' were derived from the ‘food iv desert' concept and are “areas that lack adequate public transit service given areas containing populations that are deemed transit dependent” (Jiao & Dillivan, 2013). As the ‘food desert' concept was successfully transferred to a different field of study (i.e., transport) (Jiao & Dillivan, 2013), and the ‘transit desert' concept was successfully modified to suit the South African context (Vanderschuren et al., 2021), it was concluded that a similar methodology could be developed for the field of road safety. In the initial stages of developing this new ‘road safety desert' methodology, the key data requirements were identified as fatality data, including infrastructure-related data and fatalities per road user type, and road user distribution data, all at the disaggregate Transport Analysis Zone (TAZ) level (sourced from the Integrated Provincial Accident System (2011-1015) and the National Household Travel Survey (NHTS) (2013)). Due to data availability, Cape Town was chosen as the case city where this new methodology could be tested to provide proof of concept. ‘Road safety deserts' are defined as areas where there is a significantly higher road safety risk compared to the average road safety risk in the study area. Safety values (using fatalities per road user type) were subtracted from supply quality values (using infrastructure-related attributes) to determine an overall ‘safety desert' value for each TAZ. This value represents the road safety risk of an area and can be calculated for different road user types. A positive overall ‘safety desert' value indicates that there is a lower road safety risk than the risk for the average person in the study area, and vice versa. The ‘road safety desert' methodology was applied to Cape Town in order to provide a proof of concept. For motorised transport, Kraaifontein and Blue Downs were identified as ‘road safety deserts', i.e., having a road safety risk which is significantly higher than the risk to the average Capetonian. On the other hand, Durbanville and Sea Point were found to have a significantly lower road safety risk than the risk in other areas. For non-motorised transport (NMT), Durbanville and Grassy Park were found to be ‘road safety deserts'. Belgravia, Central Cape Town, and Simonstown were identified as having a slightly lower road safety risk than the risk to the average Cape Town inhabitant. v The successful ‘road safety desert' analysis of Cape Town provides proof of concept for this newly developed methodology. However, during the analysis of the results, a few issues presented themselves, primarily concerned with the data used in this research. The supply quality data should be improved and be specific to the mode being analysed. For example, when analysing NMT ‘safety deserts', the infrastructure-related attributes should be NMT specific. Additionally, in areas where a large number of trips are made by non-residents, traffic counts rather than NHTS demand data (which is for residents' trip making only) should be used in the safety value calculation. A further consideration is the use of smaller analysis zones, which would increase the accuracy of the results. Overall, these results prove that the ‘road safety desert' methodology can be applied to a South African city successfully. While several issues did arise in the accuracy of the results, this is not inherently due to problems with the methodology, but due to problems with the data that was available to be conduct this study. It is recommended that other South African and international cities investigate the methodology developed in this study, and use it to identify areas and population groups that carry a high road safety burden. Through this analysis, a road safety strategy can be developed for the areas that need it most.

Keywords

Engineering

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