thèse doctorat de l'université bordeaux 2 - ISPED-Enseignement à ...

should be accountable for ensuring HWZ safety. 2 12 15 Further, reducing HWZ duration couldbe useful in decreasing the resulting crash risk. 15Almost half of the traffic on the highway was composed of heavy trucks which have anoverall low speed. 12 As the space to accommodate the traffic volume is reduced in HWZ, it islikely that in absence of harsher penalties and barriers, smaller and faster vehicles performedhazardous overtaking. Our results consistently showed that most of the crashes occurred as aresult of traffic conflict between the oppositely moving traffic in the work zones (figure 1B). 21This points out the need to carefully plan and regulate the traffic flow during maintenanceworks. Enforcing harsher penalties for overtaking, providing alternate lanes, and trafficseparation might be some of the useful measures to decrease hazardous situations leading toHWZs crashes in Pakistan. 15This study showed that pedestrians, probably including workers, were significantly involvedin HWZ crashes. Sudden entry onto the highway was reported as the major cause of suchcrashes. Similarly, wet surface increased the risk of HWZ crashes. Such involvements,although less important, were found in HWZ crashes elsewhere. 10 Human judgement error isindeed one of the principal factor identified in HWZ crashes. 1 10 These results indicated thatprevention measures such as advance warning area, clear zones to enhance visibility, roadmarkings, hazard signage in the work area, and conspicuity equipment for workers could beuseful to reduce such crashes in Pakistan. 3 15Finally, the overall traffic fatality risk on this highway is several times higher as compared toa limited access road in the HICs. 24 Factors such as drowsiness, speeding, hazardousovertaking, and poor vehicle condition were highly involved in these crashes. 25 26 Theseresults were not surprising as the traffic conditions are quite different from HICs which hadmore crash prevention and control measures on their roads. 21 Interestingly, the fatality risk forthe occupants of cars, minibuses, and buses were two times or more high than for thosetravelling in trucks. The higher fatality risk associated with car and bus occupants ascompared to truck occupants could be due to the high number of passengers and the non useof seat belts by both drivers and passengers, substandard vehicles, and higher traffic speeds. 26This study demonstrates the need to investigate and control high vulnerability of caroccupants in LMICs.This study may have some limitations. Firstly, we included only police reported crashes,which were shown to report only 56% of road fatalities and 4% of severe injuries inPakistan. 27 Thus given results could under estimate the crash risk which we had assumed to besame for both the HWZ and normal traffic zones. Further, traffic measuring was based on 24-hour surveys. This could lead to both underestimation and overestimation of the crash risk. 17Nevertheless, these had been used previously to compare the crash risk for vehicles and roadtypes in LMICs. 21 Finally, little information was available on involved drivers to account forthose factors in adjusted analyses. 1Pakistan, like many other LMICs, is passing through economic transition. 12 With the expectedincrease in HWZ activity in the future, several lessons could be learnt from this study. Firstly,a high road injury burden in HWZ indicated that a monitoring system is needed to examinethe HWZ safety measures by the agencies involved in maintenance works. 15 Secondly, moreefforts are required to reduce the duration of HWZs. 2 Finally, these results orient towardprevention measures such as harsher punishment for traffic violations such as overtaking,traffic separation, advanced warning area, hazard signage, and improving pedestrians’115