HVE White Papers
Engineering Dynamics Corporation Reconstruction of Accident Speeds on the Highway
EDCRASH is a reconstruction analysis
of single- or two-vehicle accidents, including collision. Based on the CRASH
model developed at Calspan and extended by NHTSA, EDCRASH also includes
several enhancements developed by EDC, including hard spots on the vehicle
exterior and an extensive set of run-time diagnostics that help confirm valid
The primary purpose of EDCRASH is to determine impact speed and delta-V (a measure of impact severity) based on accident site and vehicle damage measurements. EDCRASH is also well-suited for collisions with immovable
barriers, such as bridge abutments and large trees.
EDCRASH has been validated using the RICSAC collision experiments, a
set of 12 well-instrumented staged collisions. Several validation studies have
been published in the technical literature.
EDCRASH is a 2-D, 3 degree-of freedom (X,Y,PSI) analysis for each
vehicle. For oblique impacts, EDCRASH uses the conservation of linear
momentum; for collinear collisions, vehicle damage is used in conjunction with
crush stiffness coefficients derived from barrier crash testing. The
impact-to-rest phase is analyzed using energy methods and a modified Marquard
method allowing for the effects of vehicle rotation and curved trajectories. The
impact-to-rest phase may also be confirmed by a trajectory simulation.
First introduced in 1984, EDCRASH has since become universally recognized as the industry standard reconstruction program. No other reconstruction program has been so well documented, validated and critically reviewed as EDCs EDCRASH. Numerous validation studies are published in the technical literature.
If you would like to see an example of how to use EDCRASH, download the Tutorial from the EDCRASH Physics Manual. (Download time for this 1.1 MB Adobe PDF file is about 1 - 5 minutes, depending upon your connection speed.)
- Selectable from HVE-CSI’s built-in database, according to Type (Passenger Car, Pickup, Sport-Utility, Van, Truck and Fixed and Movable Barriers).
- All parameters are user-editable.
- Work directly on a scaled crash site diagram or aerial photograph.
- Local gravitational constant.
- Drag-and-drop positioning of vehicles in the environment.
- Driver Controls (wheel lock-up, steer angle, rotation/lateral skidding and pre-impact braking).
- Simulation Controls (integration timesteps and termination conditions).
- Vehicle Damage (CDC, PDOF, width, depth, offset, and impulse center).
- Accident History (positions and velocities at each path position: begin braking, impact, separation,
- Damage Data (profile, CDC, PDOF, delta-V).
- Vehicle Data (dimensions, inertias, stiffness coefficients, tire properties, wheel lock-ups).
- Messages (event related diagnostics).
- Program Data (complete listing of user-entered scene data).
- References (list of supporting technical publications).
- Site Drawing (display of vehicle impact and rest position, end of rotation, point on curve and key data).
- Damage Profiles (display of vehicle damage outline and key damage data).
- Momentum Diagram (vector diagram of pre- and post-impact momentum).