This speed calculator has been designed to offer to accurate results with core information. Receive immediate results with the following entries:

Length of skid marks (Feet):
Choose surface conditions:	Dry Concrete Dry Blacktop Dry Grass Wet Concrete Wet Blacktop Wet Grass

Common methods used to determine speed in a collision:

1. Skid Marks

• Needed
  • Distance
  • Friction
  • Roadway Grade
• Results: Minimum Speed

2. Time Distance

• Needed
  • Distance Vehicle Traveled
  • Velocity/ Speed Conversion Factor - Speed x 1.466 = Velocity, Virginia Code 46.2-880
  • Suspected Speed Results
• Results
  • Actual Speed
  • Avoidability Issues
  • Witness Credibility

3. Yaw Marks

• Needed
  • Radius
  • Friction
  • Superelevation
• Results: Actual Speed

4. Momentum

• Needed
  • Vehicular Gross Weights
  • Approach Angles
  • Departure Angles
  • Post Impact Speeds (Skid Formula)
• Results: Very accurate speed estimates at the point of impact

5. Fall, Flip, Vault

• Needed
  • Point of Impact
  • Point of Final Rest
  • Distance Airborne
  • Departure Angle
  • Roadway Friction
• Results: Very accurate speed determination at the time of the event

6. Collision Damage

• Needed
  • Depth of Engagement
  • Width of Engagement
  • Manufacturer's Crush Specifications
• Results: Very accurate speed at impact

7. Crash Data Retrieval System

• Needed
  • 1990 - 1997 GM Vehicles- limited data
  • 1998 - forward GM Vehicles- all data
  • 2000 - forward, all vehicle research and development
• Results: Computer Download Information
  • Type I
    • Near Deployment Event
    • Air Bag Does Not Deploy
    • Event Stored Until Ignition Cycled 250 Times
  • Type 2
    • Deployment Event
    • Pre Crash and Crash Data
    • Cannot Be Erased
  • Information
    • Velocity Change (DeltaV)
    • Vehicular Speed
    • Brake Switch Circuit Status
    • Driver Seat Belt Circuit Switch Status
    • Passenger Front Airbag Suppression Switch Status
    • Time Evaluations