Task 2

Suppose a car left a skid mark of d feet long. The above formulas will estimate the speed s in miles per hour at which the car was traveling when the brakes were applied.

 1Complete the table



  

 Why do you think the estimates of speed do not double when the skid marks double in length

 Because a car on a wet road will slide further than a car on a dry road.

 Because of the use of friction brakes and wheels on the street.

 Based on these results, what conclusions can you make about a safe following distance

 Driving on the appropriate speed and distance to stop and not be surprised, That will avoid accidents.

 when the car is driven on a wet road and not on a dry road it double the speed and you will not stop at the same time u try to stop the car

 

Task 3

Task 3

The formula d = 0.044s2 + 1.1s relates the maximum speed s in mph that you should travel in order to be able to stop in d feet.

Suppose you have 150 feet (about 10 car lengths) between your car and the car in front of you. Find the maximum speed you should travel to avoid a collision.

d = 044s2+1.1s
150 = 0.044s2 + 1.1s
0.044s2 +1.1s – 150 = 0

Solve by this way: S = -b ± √ b2 – 4ac

Or by finding delta d

S1= 47.2         S2=-72.2

We will take the positive number which is equal to 47.2 .. the negative number is rejected.



Driver Reaction Time

The ability to predict the response of a vehicle in a stream of traffic to the behavior of its predecessor is important in estimating what effect changes to the driving environment will have on traffic flow. Various proposed to explain this behavior have different strengths and weaknesses. The paper constructs a new model for the response of the following vehicle based on the assumption that each driver sets limits to his desired braking and acceleration rates. The parameters in the model correspond directly to obvious characteristics of driver behavior and the paper goes on to show that when realistic values are assigned to the parameters in a simulation.

Summarized Road Rage and Accident Probability

About the AAA Foundation for Traffic Safety

The first study in this volume was sponsored by the AAA Foundation for Traffic Safety. Founded in 1947, the AAA Foundation for Traffic Safety is a not-for-profit.

A Message From The Sponsor

A 1995 study performed by the Road Safety Unit of the Automobile Association of Great Britain found that 90 percent of the drivers surveyed had experienced "road rage" incidents during the preceding 12 months. In this study, 60 percent of drivers admitted to losing their tempers behind the wheel during the previous year, and one percent claimed they had been physically assaulted by another motorist.

The Foundation realized that although the topic of aggressive driving seemed of great concern to motorists, there was little real knowledge of the extent of the problem or of any trends in the phenomenon.



Summarized Young Drivers and Auto Accidents

Teen Drivers: Fact Sheet

Motor vehicle crashes are the leading cause of death for U.S. teens, accounting for more than one in three deaths in this age group.1 In 2008, nine teens ages 16 to 19 died every day from motor vehicle injuries. Per mile driven, teen drivers ages 16 to 19 are four times more likely than older drivers to crash. Fortunately, teen motor vehicle crashes are preventable, and proven strategies can improve the safety of young drivers on the road.

How big is the problem?

In 2008, about 3,500 teens in the United States aged 15–19 were killed and  more than 350,000 were treated in emergency departments for injuries suffered in motor-vehicle crashes.1,2

How can deaths and injuries resulting from crashes involving teen drivers be prevented?

There are proven methods to helping teens become safer drivers. Research suggests that the most comprehensive graduated drivers licensing (GDL) programs are associated with reductions of 38% and 40% in fatal and injury crashes, respectively, among 16-year-old drivers.1



Summarized Automobile Accident Statistics

Car Accident Statistics

There were nearly 6,420,000 auto accidents in the United States in 2005. 2.9 million People were injured and 42,636 people killed. About 115 people die incident walk in America every 13 minutes, in 2002there were an estimated 6,328,000 car accidents in the USA There were about 2.9 million injuries and 42,815 people were killed, in 2003 there were 6,328,000 and 42,643 people were killed in auto accidents, in 2000 There were an estimated 6,356,000 car accidents in the USA There were about 3.2 million injuries and 41,821 people were killed in auto accidents based on data collected by the Federal Highway Administration...



Calculating Your Braking Distance

Stopping distance are important for drivers to avoid any accident that could happen . Stopping distance is the distance you travel before you hit the other car. It's the total of two parts reaction distance and breaking distance. Reaction distance is the distance moved during thinking time before braking so the car in this time is still moving. Breaking distance generally defined as the distance traveled of a car after applying its brakes to where the car will stop. Many  variables affect the braking distance. The most important is the velocity of the car, the higher your speed the longer it will take you to stop.  The friction between the roadway and your tires can influence your braking distance also the weight of the car, the more weight cause lower breaking distance .



The National Safety Council (NSC) is a non-profit, non-government agency. It gives people specially drivers some driving rules and to be aware about the important of safety. These driving rules are:

1. Seatbelts (Wear Seat belt before starting the car engine)

2. Speed (Drive at speed limit of the road)

3. Never drink while driving.

4. Distracted driving (do not play with phone, calling or sending messages)

  5. Road rules (follow the signs and the road rules)

  6. Defensive driving (make a distance between your car and others)

How to calculate the stopping distance

for a car:

      

F: the friction force between tires and

the road.

µ: the coefficient of friction.

mg: the weight of the car.

Vo: the velocity of the car.

d: the distance traveled till the car stop.

V2: the final velocity which is zero.

KE: Kinetic Energy.

W: work by friction force.

Equation is :

KE =  m   -   m  =   -   m                                   

W = µmgd

In order to stop the car, the friction force of the road must do enough work on the car to reduce its kinetic energy to zero.

µmgd  =1/2 mvo

So to calculate distance we use this equation:

d = vo/2mg