**The Relationship Between Tire Pressure and Stopping Time**

Many factors play a role in how quickly an automobile can come to a complete stop, with one major factor being the tire pressure. Understanding which tire pressure will yield the fast stopping time while maintaining a smooth ride is crucial. With this knowledge imbedded into the minds of drivers all around the world, many accidents can be prevented. In order to answer this, a motorized tire was tested for stopping time using increasing intervals of 5 psi. A structure was built to keep the tire stable. Then, a cinderblock was raised upwards towards the moving tire using a jack. A scale was placed under the block to assure a constant force between the tire and the block was exerted each time. The time the tire took to stop after the force of the block was applied was recorded each time. These stopping times were averaged for each psi and were graphed. A regression model was used to analyze how tire pressure affected the stopping time. A quartic model was best fit for the data. It was recorded that on average, 30 psi yielded the smallest stopping time for the increments tested. By following the quartic regression model, the minimum point on the graph gave an estimate of the tire pressure needed to result in the fastest stopping time. The minimum point for the tire pressure that provided the quickest stopping time was 32.66 psi. Although the regression was quartic, the stopping distance began to rise after approximately 30 psi due to over-inflation of the tire, it was generally concluded that there is an inverse relationship between tire pressure and stopping time.

### Research Conducted By:

Tyler Johnson

*Fraser High School*

Griffin Yakey

*Fraser High School*