On what type of road do misjudgment accidents tend to occur? Incidence is studied below by location, road layout and road configuration.
Accidents examined are those that occurred on national highways, principal local roads, general prefectural roads, and municipal roads. These are bundled into two categories: "Principal road (national highways, principal local roads, and general prefectural roads)" and "Non-principal road (municipal roads)".
Location is either "Urban area" or "Non-urban area".
As for road layout, "Intersection area" and "Near intersection area" are indicated as "Intersection" and other parts of the road as "Non-intersection area". Road configuration, which is probably most closely related to misjudgment, is studied in detail, combining the configuration such as "straight" and "curve" with the slope such as "uphill" and "downhill". "Curve" refers to the curved or turning part of the road. The direction of a "right curve" or "left curve" is seen from the primary party of an accident. "Uphill" and "downhill" means a road with an incline of 3/100 or more. Combined road configuration with incline is described by "Configuration" and "Slope", in that order, as in "right curve, uphill" and "straight, level". The results of cross tabulation analysis are shown in Table 2. "Others" in the table indicate motorways, roads authorized by the Road Transport Law, etc.
|
The colored sections are intended for studying the occurrence trend of misjudgment accidents, showing the category of roads with at least 1,000 accidents and incidence of 10% or more.
Except for straight, level roads, the number of accidents and the incidence are both high in "left curve, downhill" and "right curve, downhill", on principal roads non-intersection areas in urban areas. Both are downhill curves, with the rate of incidence higher than 15%.
Next, 39,631 accidents tallied in Table 2 are analyzed by item.
Configuration of the road on which accidents took place was examined under three categories: road configuration (right or left curve), slope (uphill or downhill), and combination of the two (right curve uphill, left curve downhill, etc.). Results are displayed in Table 3.
By location, more misjudgment accidents occurred on roads in non-urban areas, both in number and incidence, compared with urban areas. The rate of incidence was about 4 times greater.
By type of road, non-principal roads witnessed a higher number and incidence of accidents compared to principal roads, but the difference was insignificant.
By road layout, non-intersection areas were more likely to be accident spots than intersections, both in number and incidence, with the incident rate being about twice as large.
By road configuration, the incidence rate was 12 times greater on a left curve than a straight road, while the incidence rate for a right curve was 10 times that for a straight road. By type of slope, the rate was 5 times greater for downhill compared to level roads, and 4 times greater for uphill. By combined configuration/slope indices, the highest rate of incidence was observed for left curve, downhill (21 times greater than straight, level roads), followed by right curve, downhill (17 times).
From the above analysis by location, road type, road layout, and road configuration, it was found that misjudgment accidents tended to occur most often on non-urban principal roads (no crossing) going downhill on a curve, both in number and incidence. Further, the results showed the greatest ratios for the incidence rates among the items in the combined road configuration category. A closer look showed that the roads going downhill on a left curve witnessed the highest incidence of misjudgment accidents.
|
