ANALYSIS OF THE EFFECT OF WEATHER ON THE OCCURRENCE OF ROAD TRAFFIC ACCIDENTS IN ZARIA, KADUNA STATE, NIGERIA

Author: Mohammed, Hamza

This thesis assessed the effect of weather on the occurrence of road traffic accidents (RTAs) within Zaria unit command of the Federal Road Safety Commission (FRSC). Thus, data for the selected weather elements which include rainfall, temperature, visibility, relative humidity, wind speed and evaporation rate and RTAs were obtained from Nigerian Meteorological Agency and FRSC respectively. Time series analysis, Pearson‘s product moment correlation coefficient, T-test, Fisher‘s method, bar graphs, multiple linear regression, one-way ANOVA were the analytical methods used. A range of statistical methods used in this study were adopted from Mondal et al. (2011c) which include rain-crash-index, wet-crash-rate, dry-crash-rate, rain-crash-effect, dry spell effect and rain-class-crash-rate. This study revealed a general increase in the amount of rainfall, number of wet days, air temperature, visibility and relative humidity and a decrease in wind speed and evaporation rate. It also showed that Zaria-Kaduna route recorded more RTA cases and casualties, dangerous drivingwas the leading causes of RTAs in Zaria and there was a general increase in the number of RTA cases and casualties in Zaria.The highest number of RTA cases recorded in a year was in 2013 and for casualties, it was in 2012. The highest number of RTA cases and casualties were recorded in July and January respectively. Furthermore, of the seven RTA variables which include fatal, serious, minor, total cases of RTA, number of passengers injured or killed and total casualties that each of the weather parameters was tested against annually and monthly for relationship, both positive and negative associations were observed showing that the relationship is not vary from one weather element to another and from one RTA parameter to another. The most predominant cause of RTAs in the study area which is dangerous driving was tested annually against the selected weather parameters and their resulting relationship showed that where DGD was found to have caused fatal RTAs, rainfall, number of wet days and wind speed were found to have influenced it positively. However, when monthly analysis was carried, the resulting relationship showed that where DGD was found to have caused fatal RTAs, rainfall, air temperature, visibility and relative humidity were found to have influenced it positively. There is a general tendency in Zaria for greater amount of rainfall to lead to more RTAs and lesser rain-crash-index, the probability that a RTA will occur on any wet day is 0.24 while it is 0.28 on any dry day while the probability that a RTA will occur on a no dry spell wet day is 0.39, 0.55 on a small dry spell wet day and 0.06 on a large dry spell wet day. Zaria revealed a negative rain-crash-effect showing that more RTA cases occur per unit dry day than unit wet day.The amount of rainfall recorded three, four or five days before any RTA had a significant positive relationship with fatal, minor and the number of passengers killedin RTAs while the amount of rainfall recorded three days before any RTA has a significant negative association with the number of serious cases and total RTA cases. Finally, class two rainfall (>1 to 2mm) has the highest rain-class-crash-rate in the study area. In conclusion, there exist a complex relationship between weather and the occurrence of RTAs and secondly, this study has proven scientifically that weather (poor or conducive) contributes to the occurrence of RTAs. It may not be a proximate factor but it combines with other factors to cause RTAs and this study went a long way to show how. Generally, it was observed that the attitude of most drivers towards driving does change significantly between the wet and dry seasons as wet crash rate and dry crash rate were 28 per cent and 24 per cent respectively. This could be due to poor understanding of drivers with regards to either the effect of weather on the occurrence of RTAs directly or the influence of weather on other causes of RTAs. Thus, all the stakeholders in the transport sector must show commitment towards reducing RTAs in Nigeria.