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IntroductionThe rapid growth of Botswana’s economy since independence in 1966 has brought more tarred roads and vehicles, accompanied by an escalating road crash fatality rate. We tested the hypothesis that motor vehicle crash fatality increases resulted from, rather than just corresponded with, annual gross domestic product (GDP) increases. Data from Zambia, adjacent to Botswana, were used for comparison.MethodsAnnual social and economic indicators and motor vehicle crash fatality rates in Botswana and Zambia were accessed from 1960 to 2012 and analysed using vector autoregressive analysis and Granger causality tests.ResultsIn Botswana, annual changes in per capita GDP predicted annual changes in motor vehicle crash fatality rates (p = 0.042). The opposite was not observed; annual changes in motor vehicle crash fatality rates did not predict annual GDP changes. These findings suggest that GDP growth in a given year caused additional road traffic fatalities in Botswana and that, on average, every billion dollar increase in GDP produced an increase in the rate of road traffic fatalities. In Zambia, annual GDP changes predicted annual fatality rate changes three years later (p = 0.029), but annual changes in road crash fatality rates also predicted annual increases in per capita GDP (p = 0.026) three years later, suggesting a correlation between trends, but not a causal effect of GDP.ConclusionRoad crash fatalities increased in recent decades in both Zambia and Botswana. But the rapid economic development in Botswana over this time period appears to have driven proportionate road traffic fatality increases. There are opportunities for newly emerging economies such as Zambia, Angola, and others to learn from the Botswana experience. Evidence-based investments in road safety interventions should be concomitant with economic development.

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Sample pre-treatment and enrichment using the supported liquid membrane (SLM) technique for the determination of phenolic nitrile herbicides in presence of carbamates in river water samples was investigated. The uncharged herbicide molecules from the flowing aqueous solution diffuse through an immobilized water-immiscible organic solvent, supported by a porous polytetrafluoroethylene (PTFE) membrane, and trapped in a stagnant acidic acceptor phase in an ionic form. Using n-undecane as a membrane solvent, the SLM extraction methodology was successfully used for the enrichment and separation of phenolic nitrile herbicides in environmental waters with extraction efficiencies of 60% or better. A RDS (%) of 2.1 and 1.8 was obtained for the extraction of ioxynil and bromoxynil from river water, respectively.