Application to Estimate Distance Taken to Stop a Car

It is well known that the greater the car's speed, the higher is the arrest distance.

This Shiny online application estimates the distance taken to stop a moving car. The user inserts the car's speed and obtains the distance. Furthermore, the user selects one of two regression models used in the estimation.

The application uses R dataset cars containing a collection of the speed of cars and the distances taken to stop.

There follows a bief description of the dataset.

str(cars)

'data.frame':   50 obs. of  2 variables:
 $ speed: num  4 4 7 7 8 9 10 10 10 11 ...
 $ dist : num  2 10 4 22 16 10 18 26 34 17 ...

The application approximates this data fitting the regression model. The model is selected by the user between linear and quadratic forms.

The linear form is: \( dist = \alpha + \beta * speed \)

model1 <- lm(dist ~ speed, cars)

The quadratic form is: \( dist = \gamma * speed^2 \)

cars$speed2 <- cars$speed^2
model2 <- lm(dist ~ speed2 - 1, cars)