فصلنامه راهور
پیاپی 18 (تابستان 1391)

One of the parameters related to the surface of asphalt layers that can be effective on road accidents is reduction of skid resistance in joint surface between a vehicle tire and asphalt layer. The relationship between skid resistance and crashes has been studied from years ago, while quantitive relations among these variables have not been determined completely. This article has reviewed the analysis of skid resistance impact on road accidents along with traffic statistics. In this study, using flat tires, skid resistance in wet conditions has been measured by locked wheel and compared with crashes rate in wet conditions. In addition, the impact of traffic volume on crashes rate has been investigated. This article has utilized the traffic information and statistics of one of the USA states as a case study. After collecting data, raw information has been processed and grouped and then additional statistics deleted. Crashes statistics in one-mile sections were calculated and divided on traffic volume of that section so that crashes rates can be evaluated. The least skid resistance in each section considered as skid resistance of that section. The analysis of results represents that there is a very proper statistics relation in viewpoint of skid resistance impact on crashes rate. As reducing friction number, crashes rate has been increased; although as expected, crashes rate cannot be modelled just by fraction number. Moreover analyzing relationship between crashes rate and traffic volume concludes that crashes rate has been reduced by increasing trafficvolume.

To reduce human factors as the most common cause of fraction in the road traffic injuries new traffic regulation was established, but its effect is not evaluated. The effect of new traffic regulation on the rate of fatalities and injuries due to hazardous violations is evaluated by this study. It was an overtime controlled trial of intervention. All subjects which faced to fatal and non fatal injuries caused by six risky fractions (speeding, overtaking, red traffic light crossing, zigzag movement, reverse gear movement in the highways, vehicle impoundment in two simultaneous fractions) during defined period of time, from (June 2010 to November 2010 as control and June 2011 to November 2011 as case groups. Existing FAVA and forensic data was used and the effect of fatal and non- fatal related factors with new regulation was analyzed.) New traffic regulation leads to reduction of fatality and injury of road traffic accidents in urban and rural ways after implementation and its trend was continual during six months. Reduction of fatality and injury of road traffic accidents was higher among 20-29 years age groups after new traffic regulation. The effect of new traffic regulation on reduction in fatalities and injuries was: 8.7 and 33.3 percent respectively. Totally first phase of new traffic regulation had a positive effect on fatality and injury rates due to road traffic crashes. High perseverance and corrected new traffic regulation can be more effective in maintaining and increasing effectiveness. The impact of new regulation should be investigated in some of provinces.

Annually, many vehicle crashes happen in the world because of driver drowsiness (fatigue) or distraction (inattention). These crashes lead to many fatalities and losses. Driver face monitoring is one of the main approaches for driver drowsiness/distraction detection. A system based on this approach gets an image sequence from camera and process it to extract drowsiness and distraction symptoms from driver's face. In this article, a driver face monitoring system is designed that estimates driver hypo-vigilance based on extracting symptoms from eye regions. In proposed system, two features are extracted: (1) percentage of eye closure (PERCLOS) and (2) eye blink rate. Experimental results on some sequences that captured in both real conditions (in vehicle) and laboratory conditions show that proposed system is accurate in feature extraction and hypo-vigilance estimation.

The growth of fatality rate due to driving accidents has created remarkable concerns and attempts for recognizing and controlling causes of crashes occurrence from the part of responsible officials. Although the general belief is that human factor plays the main role in driving accidents, yet there are disputes over this issue. In road transportation, fatigue is one of the main causes of human errors which can lead to fatal accidents. Due to being unknown and difficult to be recognized as a factor involved in accidents, fatigue has been less paid attention. Fatigue in general means decline and collapse of an individual,s energy. Fatigue by itself made by extended and complicated factors. The driver,s fatigue impairs his ability to drive and make proper decisions that can lead to hazardous outcomes. Fatigue emerges with signs like slow reaction, devour of direct path, reduction of brake track, heaviness of eyelids and drowsiness. The role of place and time parameters has also been studied separately. Most accidents as a result of fatigue occurred in periods of 0 to 6 AM and 2 to 4 PM. As expected, two ways rural roads are the most possible spots for crash›s occurrence that their causes are fatigue. Action for improvement of road environment can play an important role in preventing from drivers, fatigue. In this study, we,ve tried to investigate main causing factors of drivers, fatigue. And if it is possible to present proper guidelines for addressing the problem, including installation of messaging signs warn for driving while tired risks and fatigue management, proper roads geometric design, legal surveillance, warning system and technical system of vehicles, and obligating drivers to take rest in the path along with considering rest places.

Relationship among life quality, safety, reduction of damages and traffic costs especially accidents through stable development index has already been emphasized. There are various definitions, philosophies and views about human life value. Among different economic evaluation methods of traffic accidents, "human capital" despite of its shortcomings is still progressive in application. In Iran, this method along with "blood money" method have still the most applications. Existing up to date laws, regulations and instructions and using special techniques, evaluation and audition of risk prior to performing plans along with a collection of managerial measures, people participations, and studies led to remarkable successes in road safety promotion and crashes reduction in developed countries. These measures and techniques can be placed on the agenda of local measures and practitioners by the support of laws, regulations and instructions. We can take advantage of developed countries experience for road safety in Iran. There are deficiencies in viewpoint of evaluation method introduction, fatal crashes definitions, items involving accident costs, and applied diffrent laws, regulations and instructions in national scale. the extent of accidents and traffic costs and those enforced on people and road officials are much more than such values that informed or imagined.

Study prior to and following a practice considers as one the evaluation method of saftey measures impacts. In this evaluation method, crashes number index is usually used for comparison of conditions prior to and following the implementation of safety measures. In this way, it seems to be necessary to present a method for evaluating effectof saftey measures on injurial accidents share in the cases that the goal of saftey is reduction of injurial crashes. The most important part of previous and later studies is predicting accidents by the supposition of lack of saftey measures implementaion. In this prediction, it should be included changes effected on prediction indexes in lapseof time. In this article, correction coefficient based on total accidents for properly predicting crashes number in the period following the implementation of measures has been suggested. Such a coeficient has been applied in a case- study for effect measuring seat belt wearing on injurial crashes in Kuwait. The results concludes that applying this correction coeficient provides the expected seat belt wearing effect.