Abstract
Aim: The aim of the present paper is to analyse time trends in transport services trade and to
determine associations between gross domestic product (GDP) growth and transport services
trade for South Africa.
Methods: Associations between economic growth assessed through GDP as primary exposure
and transport services for both exports and imports are reported for South Africa. Four
indicators were used to assess transport services trade namely; percentage of commercial
service exports; percentage of commercial service imports); percentage of service exports,
balance of payment (BoP)] and percentage of service imports, BoP). Regressions were
computed using Joinpoint statistical software to assess overtime trends for both exports and
imports for transport services between 1992 and 2016. Trends in transport exports and imports
services were assessed by calculating annual percentage changes (APC) using linear
regression: ratey b0+b1 y with log (ratey) being the natural log of transport services (% of
commercial service exports) in year y for example. APC in these services are reported and
discussed.
Results: Significant decreases in transport service exports were observed between 1993 and
1997 (APC = -6.33 p-value <0.05) and 2011 and 2016 (APC = -4.18 p-value = <0.05).
Additionally, non-significant percentage increases in transport services exports were observed
between 1997 and 2001 (APC = 4.61) and 2004 and 2011 (APC = 2.3). Both a significant and
non-significant increases in transport service imports was observed between 1993 and 2007
(APC =1.19 p-value <0.05) and 2010 and 2014 (APC=4.86) respectively. Additionally, nonsignificant
percentage decreases in transport services imports were observed between 2007 and
2010 (APC=4.61) and 2014 and 2016 (APC=2.3). Though slightly different over time trends
estimates in terms of the APC of observed for transports service exports and imports, BOP they
were similar and comparable to commercial transport service exports and imports respectively.
Overall, there was no correlation between GDP and transport service trade.
Conclusion: This study indicates that despite good ranking on the quality of infrastructure in
Africa, South Africa has been experiencing a deficit transport services trade overtime. In
addition, the results show that transport services trade was not trend associated with GDP
growth in the time reported in the current study, as various fluctuations were observed.