Understanding Closing Speeds: Why 1 Second Is Not Always the Same

Closing speed is the relative velocity between two cars. A one-second gap between a GTP and a GT3 car on a straight disappears at a rate of nearly 40 meters per second. This means the faster car will reach the slower car bumper much sooner than a driver might expect. The one-second rule must be adjusted based on the track location. On a long straight, one second is a safe margin to plan a move. In a high-speed cornering sequence, that same one second can vanish instantly as the prototype carries significantly more mid-corner speed. Effective racing requires calculating these vectors in real-time to ensure the overtake happens on a straight rather than in a vulnerable braking zone.

The Geometry of the Overtake: Speed Vectors and Corner Entry

One of the primary causes of multiclass incidents is the vast difference in braking points. A GTP car can often brake 50 meters later than a GT3 car at a corner like Monza's Turn 1. If a prototype driver attempts to follow a GT3 car directly into the zone, the closing speed becomes an unavoidable collision. The key is to use an offset line. By positioning the faster car to the inside or outside before the braking zone, the driver creates a safety buffer. This communication through positioning tells the slower car exactly where the faster car intends to be, reducing the chance of the slower car turning in on a prototype they did not realize was there.