Jung Gon Sung

Analysis on Factors Affecting Traffic Accident Severity - Case Study : Arterial Included Curve Section -

The main causes of traffic accidents can be classified by 3 factors - human error, vehicle deficiency and road environmental problem and most accidents occurs not only 1 factor but combination of 2 or 3-factors. Among these factors, road environmental factor is the most important factor due to influence the behavior of cars and road users and road environmental factor affects 30% of total accidents approximately. The 5 years traffic accidents data analyzed to verify the accidents severity on Korea National Highways. In order to analyze the severity, Ordered Probit Model was used. As a independent variables of this model the number of lane, neighbor road environments, sight distance, vertical grade, lane width, shoulder width and traffic volume were used and as a dependent variables the minor injuries, serious injuries and fatalities were used. Research results shows that sight distance and lane width are identified as significant factors for the traffic accident severity and lesser sight distance and lane width shows greater traffic accident severity.

Study of the Influence of Condensation on Road Signs to Drivers

PURPOSES : This research is to analyze the influence in terms of misreading rate and legibility time for drivers when condensation occurs on the road signs. METHODS : In this research, the dew occurred road signs provided to drivers to measure legibility time and misreading rate to compare with normal road sign. In order to identify the difference of legibility time between normal road sign and dew occurred road sign, the T-test and ANOVA test were used. And the vision system was used to recognize the region of dew occurrence on the road sign, then the brightness of dew occurrence region on the road sign was changed to check the misreading rate of drivers according to the change rate of brightness. RESULTS : The legibility times were measured 2.65s for normal road sign and 4.08s for dew occurrence road sign and misreading rates were measured 2.8% for normal road sign, 21.7% for dew occurrence road sign.

Performance of Dual Strength Median Barrier System

There had not been any median barrier that satisfied the impact performance criteria of SB4 level specified in 2001 Korean Design Guide. In the situation, new median barrier composed of composite steel tube post and steel beam section having two different stiffness have been developed. Reinforcing steel tube post with partial concrete filling increased the ultimate moment capacity considerably, which was verified by a simple beam test. Beam section composed of two parts of different thickness helped to accomodate both truck and passenger car effectively by increasing stiffness for truck and decreasing it for passenger vehicle. Blockout with V-notch effective in reducing impact severity and rideover potential has been developed. The barrier system compoed of the dual strength beam, V-notched blockout and composite steel post with 2.5 m spacing satisfied SB4 level impact performance e criteria. This paper describes the development procedure of each member and whole system using analytic and experimental works. Also, performance to the new design guide has been verified through the computer simulation and crash test.