Head-On Crash Kinematics & Evasive Reaction Simulator

2D Rigid-Body Physics Stage READY

Source Case (Sussex Event): "A Ford Transit van travelling at ~50 mph on my side of the road suddenly filled my windscreen. With ~1s before head-on impact, I forced the car left..."

Closing Speed: 80.0 mph

TTI: 1.00s

PRT: 1.00s

PRESET SCENARIOS

Primary Speed: 30 mph

Oncoming Speed: 50 mph

Reaction Delay (PRT): 1.0s

Evasive Steering Angle: 15°

Road Surface Friction (μ): 0.70

Oncoming Van Mass: 2200 kg

Impact & Telemetry Diagnostics

Closing Speed

80 mph

117.3 fps

Perceived Distance

117.3 ft

@ PRT Window

Head-On Kinetic E.

684.2 kJ

Direct Axis Combined

Impact Force (G)

18.4 G

38.5% Dissipation

KINETIC ENERGY & IMPULSE DISSIPATION OVER TIME

Physics Note: Kinetic energy scales quadratically ($E_k = \frac{1}{2}mv^2$). Forcing an off-axis angle $\theta$ transfers direct momentum into side angular velocity and rotational shear, converting full head-on rigid axial deceleration into reduced lateral force vectors.

Closing travel, energy and the saved angle heuristic

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Read the explanation

The reaction simulator has two approaching vehicles at thirty and fifty miles per hour. It adds their speeds to get closing speed eighty miles per hour, or about one hundred seventeen point three three feet per second. Multiplying by one second of reaction time gives one hundred seventeen point three three feet of closing travel. Halving reaction time to point five seconds halves this travel. This describes relative separation in the saved model, not the distance each car travels individually. The source computes total kinetic energy by adding one half mass times speed squared for each vehicle. Its masses are fourteen hundred and twenty-two hundred kilograms. With the saved thirty and fifty mile-per-hour speeds, total kinetic energy is about six hundred seventy-five point five kilojoules. Raising only the first speed to sixty quadruples that vehicle contribution. The second contribution stays the same. The bars compare total energy before and after that one input intervention. The angle display is a heuristic rather than a collision-energy conservation solver. At exactly zero degrees the reduction is zero. At any positive angle the source adds twenty-five percentage points to one minus cosine angle times one hundred, then clamps it at eighty-five. At fifteen degrees it reports about twenty-eight point four percent. At thirty degrees about thirty-eight point four percent. The abrupt zero-to-positive-angle change is part of the saved rule. It must not be used to infer that an evasive maneuver is safe in a real crash.