View obstructions on corners.
Physical obstructions on roadway.
Type of adjacent property.
Irregularities such as potholes and dips.
Condition diagrams may indicate obstructed view as a contributory cause of accidents. A driver
proceeding at normal speed on one street should be able to see another vehicle approaching at normal
speed from an intersecting street. Obstructions reduce this visibility.
A driver should have the time and visibility to react and brake a vehicle.
Any obstructions increase the stopping distance. In the same condition diagram above, the dotted lines
represent the required visibility triangle; the shaded portions show the actual visibility triangle.
A condition diagram can be made in conjunction with a field observation of the accident location.
Reenactment of a collision can be made. The field observation should be made under the same
weather and light conditions indicated during most of the traffic accidents.
4. Analyzing and Summarizing.
Facts gathered from accident studies should be presented in terms which are understandable and
meaningful. This will help justify any recommendations made.
The repetitive principle of collisions suggests that if certain conditions influence driver, vehicle,
roadway, or control, an accident may occur. In other words, past performance is used to predict future
Studies have shown an inverse relationship between violations, citations, and accidents. As proper
traffic citations increase, accidents decrease. A useful tool in showing this is the enforcement index
(El). This is the ratio of all moving traffic violations divided by the number of accidents. This index is
then used to show fluctuations by day, week, or month, and enable adjustments to enforcement
After your study is completed,
Recommendations may include--
o Increased vehicle inspection standards.