According to Munteanu’s publication on “Humanand Environmental Factors Contributing to Fatal Road Accidents in a RomanianPopulation”, the study conducted a research about the contributions of humanand environmental factors to the road accidents in Romania. The study analysedthe possible climatic factor involed in road accidents, specifically, thepresense of wet roads, winter condition, fog, and darkness. They found out thatamong the climatic factors , the mostfrequent factor was darkness. The risk of accidents increases if the roads donot have proper lighting. PICS – wet roads,winter conditions, fog, darkness While on Lankarani’s “TheImpact of Environmental Factors on Traffic Accidents in Iran”, the study revealedthat environmental factors are major causes of road accidents.
The study foundthat dusty weather had the highest death rate while the clear weather had thehighest number of accidents compared to other weather conditions.Based on the study byShankar et. al. (1995), rainfall plays a important role in road trafficaccidents.
They claimed that high rates of fatalities resulting from roadtraffic accidents in poor weather can be explained by poor visibility because ofrainy or snowy weather and the slippery of the road surface which causesreduction of vehicle-roadway friction. In addition, Hijar et. al. (2000)supported the findings of this study. Their study showed the definite relationshipof adverse environmental conditions with traffic crashes.Based on Olawole’sImpact of Weather on Road Traffic Accidents in Ondo State, Nigeria: 2005–2012″,the study has examined the role of temperature and rainfall as it affects roadtraffic accidents in Ondo State, Nigeria.
The study has particularlyhighlighted the dual roles of temperature and rainfall. The effect of rainfallon accidents seems to be related non-linearly with accident rates. Studies havefound negative or non-significant correlations between rain and accidentsThe climatic andenvironmental condition is a factor that contributes to vehicle accidents onOndo state roads according to the study of Aiyewalehinmion “Analysis of Road Traffic Crashes/Collision in Ondo State Roads”. Weathercontributes to the wetting of pavement that reduces friction between roadsurfaces and moving vehicles. A few percentage of severe crashes occurred onOndo State roads due to effects of weather. The Figure 1shows the percentage distribution of factors responsible for crashes on OndoState from January 2005 to December 2010. It shows that the effects of weatherdoes not significantly contribute to vehicular crashes in Ondo State roads.Increasein rainfall is often linked to high accident frequencies according to the studyof Fridstrom et al.
(1995), Chang and Chen (2005), Caliendo et al. (2007),Hermans et al. (2006). However, based on the study of Karlaftis andYannis (2010), found that, contrary to the previous research, increases inrainfall reduce the total number of accidents and fatalities, a finding that causedby more cautions behaviour of the driver. The time varying effects of rainfall have also beeninvestigated.
Eisenberg (2004) has shown that the impact of precipitation on agiven day is reduced when precipitation was observed in the previous days,which is possibly due to driver adaptation. In addition to this, Brijs et al.(2008), have confirmed Eisenberg’s finding that the longer the “dry spell”, thehigher the number of accidents when rainfall occurs. Enete and Igu (2011)examined interactions between rainfall characteristics and road crashes inEnugu, Nigeria. The study established that almost 30% of road crashes in Enuguoccurred during wet months. The study also found that the effect of rainfall onroad accident count depends on the length oftime since the last rainfall.
Large dry spell days recorded more accidentcounts, supporting Eisenberg’s finding. Basedon Karlaftis’ publicationon “Weather Effects on Daily Traffic Accidents and Fatalities: A Time SeriesCount Data Approach”, the study foundthat temperature increase lead to increase onaccidents. This study verifies Scott’s discovery that higher temperatures increase accidentfrequencies. Extreme temperatures; low in winter and high in summer arepositively correlated with road accidents.
Also, the number of hours ofsunlight appears to increase road accidents concluded by Fridstom et al. (1995),Hermans et al. (2006).
Based on Brijs et al. (2008) and Stipdonk (2008), the deviationsfrom mean daily or monthly temperatures have been found to increase roadaccidents. On the other hand, Hermans et al. (2006) and Stipdonk (2008) concluded thatincreases in sub-zerotemperatures days, lower the exposure thus reducing the number of roadaccidents.