McHenry Forum - Crash Reconstruction & Simulation

Q: (rcd via email)

• A car went out of control and mounted a curb (grass median) at an approach angle of about 45 degrees. It went airborne onto the opposite side of the road, going over the bonnet of a car traveling in the opposite direction, and pushing the car and its bonnet cover to the side.
  Any ideas on how to determine the take-off angle and the trajectory of the car based on marks on the grass median and landing area, and hence the speed of the car.
  I have seen the entry by MSI Curb Impacts where a member asked about using curb height as rise and wheelbase. Unfortunately, I do not have access to SAE and hence do not have details or the conclusions of findings reported by those 4 papers, whether they contain any info useful to me. Also, are there any newer papers on the subject?
  Thank you very much for your time and effort in replying this question!

A: Hello.
1st item

• There is no restriction on access to SAE. At the time i responded to that thread on Curb Impacts the SAE site was down.
  Here are the links and each paper is available for around $17 each:
  • "Curb Impacts A Continuing Study In Energy Loss and Occupant Kinematics" SAE paper 2002-01-0557
  • "Vehicle Speed Changes and Accelerations Associated with Curb Impacts and a Comparison to HVE SIMON" SAE paper 2005-01-1175
  • Vehicle Speed Change and Acceleration Associated with Curb Impacts and a Comparison to Computer Simulation with a Multi-Point Radial Spring Tire Model, SAE paper 2008-01-0158
  • Simple Models for Analysis of Curb- and Soil-trip Rollover Events SAE paper 2006-01-0722

2nd item:

• The type of vehicle striking the curb, the curb type and height of curb make for different 'launch' or 'take-off' angles from the curb.
  Also, any roadway slope prior to the curb impact
  • was the median from a flat or curved roadway section?
  • was the median flat or sloped
  i believe some of those cited papers were to quantify the rise response of the vehicle in response to the curb impact.

I will take a look to see if any other papers which might include full scale tests of vehicle impacts on curbs and will add to this thread in the next few days.