Table 2: Explanatory variables to Contributory factors to causes of accidents.

Category of Explanatory Variables Variable Levels Effect Causes More Rear-end Accidents
Psycho-somatic Stress- - -
Calm - + -
Nervous, or hot-tempered[8] - --- Angry, aggressive drivers are a significant psychological and health hazard on the road
Poor Health Condition - -
Anxiety and insomnia - -- Causing serious accidents
Social dysfunction [9] - -- -
Depression - -- Causing serious accidents
Physical health [8] relationships existing between personality, emotion, and behavior, and indicating that public self-consciousness interacts with anger to influence aggression while driving --- Angry, aggressive drivers are a significant psychological and health hazard on the road
Road Environment Factors- - -
Number of lanes Others vs. 2-lane / -
6-lane vs. 2-lane / -
4-lane vs. 2-lane - 2-lane
Divided/undivided highway Undivided vs. divided - Divided
Accident time Night vs. daytime -- Day time
Road surface condition [10] Wet vs. dry ++ Wet
Slippery vs. dry ++ Slippery
Light condition ---- -
Urban/rural urban vs. rural + urban
Highway character curve upgrade/downgrade vs. straight-level + curve upgrade/downgrade
curve-level vs. straight level + curve-level
straight up/downgrade vs. straight-level + straight up/downgrade
Speed limit [9, 10] 55 mph vs. 25 mph ++ 55 mph
50 mph vs. 25 mph ++ 50 mph
45 mph vs. 25 mph ++ 45 mph
40 mph vs. 25 mph ++ 40 mph
35 mph vs. 25 mph ++ 35 mph
30 mph vs. 25 mph ++ 30 mph
Check your speedometer and discover that you are unknowingly traveling faster than the legal limit. ---
Striking drivers - Driver characteristics- - -
Alcohol/drug use[11] Alcohol under influence vs. No + Alcohol under influence
Drug under influence vs. No + Drug under influence
Alcohol-Drug under influence vs. No + Alcohol-Drug under influence
Had been drinking vs. No + Had been drinking alcohol
Drink on the way back from a party, or pub, even though you realize that you may be over the legal blood-alcohol limit. --- -
Age [10] 26–35 vs. <26 - <26
36–45 vs. <26 - <26
46–55 vs. <26 - <26
56–65 vs <26 - <26
66–75 vs. <26 - <26
>75 vs. <26 - <26
Residence [9] live in the local county vs. another county - another county
elsewhere in the state of Florida vs. another county - another county
other states vs. another county - another county
Gender [10] Male vs. Female + Male drivers
Vehicle type- - -
Accident vehicles [10] passenger van vs. passenger car + passenger van
pickup/light truck vs. passenger car + pickup/light truck
large size vehicle vs. passenger car + large size vehicle
AADT Average daily traffic flow + Higher traffic volume
Measurement of aberrant driving behavior [11, 12] Slips and lapses: for example, fail to read the signs correctly, and exit from a roundabout on the wrong road. --- -
Errors: Applying brakes too quickly on a slippery road and/or steer the wrong way in a skid. ---- -
Violations:
➢ Being impatient with a slow driver in the outer lane and overtake.
➢ Stay in a motorway lane that you know will be closed ahead until the last minute before forcing your way into the other lane.
--- -
Machinery/mechanical problems [9, 12, 13] Tire failure:
According to the Crash Stats report, “the tire problem is accounted for about 11.4% of the crashes” where vehicle failures were the cause of the crash making the tire failure the most common cause of a vehicle failure crash. Two of the most common types of problems with tires are tired blowouts and worn tire
--- -
- Brakes
According to the crash stats report, brake related problems as critical reasons accounted for about 15.4% of crashes where vehicle failure was the cited cause of the crash. Poor condition of brakes is a major factor in rear-end collisions, where the inability to stop in time causes a vehicle to ram right into the vehicle in front.
--- -
- Steering and Suspension
The third most-common critical reason for a car accident cited in the NHTSA report was a combination of steering, suspension, transmission, engine-related problems. This combination category accounted for just 3 % of the crashes cited in the report [9]
--- -
- Headlights and Taillights
In low visibility conditions, such as nighttime, foggy roads, or during storms, it becomes much harder to see other vehicles on the road[9]
--- -
- Windshield Wipers
Never underestimate the importance of the windshield wipers. When it’s raining hard, visibility is greatly reduced. Windshield wipers help clear rain and debris from the windshield, helping improve visibility so as to clarify the vision side.[13]
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+ = Positive effect, - = Negative effect, * = Significant (direction of effect unknown), / = Not significant