3. Traffic Accident Case Studies
  Several case studies, in which inadequate maintenance was assumed to have been the primary factor of the accident, are shown below.

  Case 1. Rollover Accident Due To Insufficient Tire Pressu

  [Outline of Accident (Figure 9)]
  Car A was traveling at approximately 60 km/h in the left lane of a road with two lanes in each direction when it suffered a flat tire in the rear left wheel, rendering the steering wheel inoperative. The car moved about 500 m forward before it crashed into the median strip, ran onto the shrubbery, spun, rolled over, skidded, and came to a halt.

  [Accident Pattern]
  Solo-vehicle collision against a fixed object (median strip and safety island)

  [Degree of Damage and Injury]
  Car: Extensively damaged Driver: Not injured

  [Cause of Accident (assumed)]
  The flat tire in the rear left wheel is likely to have been due to insufficient tire pressure. The car crashed into the median strip after it traveled about 500 meters at 60 km/h even though the driver lost control of the steering wheel.

  [Prevention Method]
  It is necessary to faithfully perform a daily inspection, and to correct irregularities, if any (such as inflating the tires). If you sense a flat tire or other abnormality, hold onto the steering wheel and do everything possible to keep the car in a straight direction. Avoid sudden braking, but apply the brakes intermittently to stop the car.

Figure 9  Scene of Accident

  Case 2. Skidding Accident Due to Worn Tires

  [Outline of Accident (Figure 10)]
  The driver of Car A, while negotiating a curve on a two-lane road, somehow mishandled the steering wheel, and crashed into a tree on the pedestrian sidewalk on the left side of the road.

  [Accident Pattern]
  Solo-vehicle collision against a fixed object (others)

  [Degree of Damage and Injury]
  Car: Extensively Damaged Driver: Seriously injured

  [Cause of Accident (assumed)]
  Tire pressure was insufficient, in addition to worn grooves in the tires of the driving wheels. The car seems to have skidded due to the low grip caused by such factors.

  [Prevention Method]
  Front wheel (driving wheels) tires showed tire-wear indicator bars in this case. Regularly check the tires, and if you spot worn grooves, change the tires soon, and perform other necessary maintenance.

Figure 10  Scene of Accident

  Case 3. Skidding Accident Due to Worn Tires

  [Outline of Accident (Figure 11)]
  Car A, while driving on a two-lane road at a steady speed in the rain, suffered hydroplaning caused by water in a wheel track, and skidded into the opposite lane. The driver tried to apply the brakes while steering to the left. The car spun and collided into a guardrail on the left, blocking the opposite lane. Immediately afterward, Car B collided against the right rear of Car A. The driver of Car B, driving at a steady speed in the rain, with poor visibility, was unable to circumvent Car A that stopped suddenly and obstructed his passage.

  [Accident Pattern]
  Vehicle-to-vehicle Frontal crash

  [Degree of Damage and Injuries]
  Vehicles: Slightly damaged Drivers: No injury

  [Cause of Accident (assumed)]
  Rear-wheel tires of Car A were worn. The accident occurred due to compound causes: driving with worn tires, weather conditions, and drivers¡Ç operation.

  [Prevention Method]
  Perform regular inspection faithfully, and maintenance work (changing tires, etc.) if need be. If rain makes the road surface slippery and causes poor visibility, slow down to a speed that allows you to stop immediately upon spotting any abnormality ahead.

  Note: Hydroplaning - a phenomenon in which tires float up onto a film of water, as tire grooves become incapable of shedding water.

Figure 11  Scene of Accident

  Case 4. Accident Caused by Damage to Leaf Spring

  [Outline of Accident (Figure 12)]
  Truck A, carrying 8-10 tons of lawn grass on a platform with a maximum load of 4 tons, was driving at 50-60 km/h on a one-lane road. Seeing a car coming from the opposite direction, the driver moved to the left to let the car pass, when suddenly the truck tilted to the left, depriving the driver of control, and rolled over on the passenger side.

  [Accident Pattern]
  Solo vehicle Running off the road (others)

  [Degree of Damage and Injury]
  Truck: Slightly damaged Driver: Slightly injured

  [Cause of Accident (assumed)]
  Truck A seems to have been habitually overloading cargo. Overloading must have caused the leaf springs to suffer metal fatigue, eventually breaking down on the road.

  [Prevention Method]
  Always perform inspection before hitting the road. Cargo carriers especially require inspection of leaf springs and other suspension mechanisms.

Figure 12  Scene of Accident

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Institute for Traffic Accident Research and Data Analysis (ITARDA)