1 / 12

240 likes | 1.36k Vues

Skid Marks and Accident Reconstruction – The Skid Mark Equation. Officer S. Chavarria #513 Chandler Police Department 602-565-8721. LG#5: Demonstrate VELOCITY and SPEED as a rate of CHANGE OF POSITION OVER TIME Slamming on the brakes locks your brakes. What forces create a skid mark.

Télécharger la présentation
## Skid Marks and Accident Reconstruction – The Skid Mark Equation

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Skid Marks and Accident Reconstruction – The Skid Mark**Equation Officer S. Chavarria #513 Chandler Police Department 602-565-8721**LG#5: Demonstrate VELOCITY and SPEED as a rate of CHANGE OF**POSITION OVER TIMESlamming on the brakes locks your brakes. What forces create a skid mark**Skid length**• Determines the speed the vehicle was traveling • Determine who was at fault or if traffic violations occurred**ESTIMATE SPEED**• To estimate speed when brakes were applied you will need the following: • Measure the skid marks • Estimate drag coefficient • Determine braking efficiency**WHAT DO YOU NEED?**S1: SPEED d1: Average Distance of Skid Marks f: Drag Coefficient**STEP 1**• Measure the skid marks • If there are several measure all of them**STEP 2**• Find the average of the distances by adding each skid and dividing the total by the number of skid marks**STEP 3**• Estimate the drag coefficient based on the surface on which the car was driving • The drag coefficient represents how much the road contributes to the stopping car • The lower drag coefficients represent slicker roads.**STEP 3 (cont.)**• EXAMPLES OF DRAG FACTORS: • Asphalt: 0.50 to 0.90 • Gravel: 0.40 to 0.80 • Ice: 0.10 to 0.25 • Snow: 0.10 to 0.55**STEP 4**Estimate the speed by taking the square root of the product of 30 times the average skid distance times the drag coefficient**Measurements must be taken in feet**• Skid marks from a vehicle with anti-lock brakes will leave dashed skid mark but you should still measure from the start of the dashes

More Related