no67 2007
Accidents Caused by Misjudgment of Road Conditions

  "The bend was sharper than I had thought." "The road went uphill more steeply than expected."
"I didn't realize the road surface was icy."
Misjudging the road configuration and conditions can lead to traffic accidents - the vehicle skids off the road and crashes into a utility pole or other structure, or into the opposite lane and collides with an oncoming vehicle.
This issue of ITARDA INFORMATION analyzes such "misjudgment accidents" caused by driver error in estimating road configuration and conditions.
  Although misjudgment accidents occur less frequently than other types of accidents, many readers have mostly likely experienced that blood-chilling moment when a curve is miscalculated.
These types of accidents often have serious results.
Even if you are "looking", you may still misjudge what you see.
  The analysis in this issue takes the concept of misjudgment accidents and presents its actual state in a systematic and quantitative manner. Make sure that you understand which road layouts and conditions most often lead to accidents, and be more aware of them when you drive. We hope this report will help prevent such misjudgment accidents.

1. How Misjudgment Accidents Occur

2. Incidence of "Misjudgment Accidents" by Road Layout and Configuration

3. Environmental Factors Affecting Incidence of Misjudgment Accidents

4. Driving Speed in Relation to Misjudgment Accidents

5. Case studies


  This issue of ITARDA INFORMATION analyzed accidents involving four-wheeled vehicles caused by the driver's misjudgment of road configuration and conditions, and presented the current situation.

  From the analysis, it was found that such accidents tend to result in more serious consequences than other types of accidents. The road configuration most frequently involved was a left curve downhill. As in traffic accidents in general, misjudgment accidents occur more frequently in unfavorable road conditions, such as snowy or foggy weather, as well as icy or snow-covered road surface. Speeding also causes such accidents.

  As a preventive measure, it is important to stick to the basics: always watch and judge the road conditions when behind the wheel, and drive at a safe speed on curves and slopes, especially under tricky road conditions. As for road management, it is important to provide information on road configuration and conditions.
Such measures as installing light-emitting delineators, roadway information service devices, high-luminance road surface markings and road lighting should be stepped up. Drivers should take advantage of this information to assess the road environment properly. Taking these measures should help reduce misjudgment accidents.

  *1 ITARDA Information No. 3 "Fatal Accidents at Night"
  *2 ITARDA Information No. 25 "Characteristics of Expressway Accidents and Preventive Measures"
  *3 ITARDA Information No. 34 "Increase in Vehicle Driver and Pedestrian Fatalities during Rainfall"

Institute for Traffic Accident Research and Data Analysis (ITARDA)