Racing line
The optimal path around a race course.
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The racing line, often called simply 'the line,' is the optimal path a driver takes around a race course. It typically uses the full width of the track to maximize the radius of a turn, entering at the outside edge, touching the apex on the inside, and exiting back to the outside. This technique is fundamental to achieving the fastest possible lap time.
Quick Facts
- Field
- Motorsport
- Known for
- Optimal path around a race course
Facts from the source article.
Variations
The optimal line into a corner generally follows an arc of continuously changing radius, starting outside and decreasing as the car decelerates toward the inside apex, often using trail braking. After the apex, the radius increases as the car accelerates back to the outside. Variations are described by the apex's location: early or late. A late apex delays the turn-in, reaching the inside later in the corner; this lengthens the exit radius, allowing greater exit speed onto a straightaway but requiring a slower entry.
Driver Ross Bentley noted that faster corners call for a line closer to the geometric line, while slower corners benefit from a later apex to enable quicker acceleration. An early apex, turning in early, permits a faster entry but slower exit and is often considered a beginner mistake. When corners follow in close succession, the driver may sacrifice the line through earlier turns to optimize position for the final corner's exit onto the following straight.
Mathematical Basis
Determining the exact optimal racing line is mathematically complex and often computationally expensive. Algorithms aim to generate a curve minimizing travel time, considering average speed, total curvature, and total distance.
Maximizing speed while minimizing curvature and distance yields the ideal line, an optimization problem. One common solution for a mid-corner apex is the Euler spiral, where the radius changes at a constant rate: the car decelerates along a path of decreasing radius to the apex, then accelerates along increasing radius. However, this solution has been challenged as merely close-to-best, as it can usually be outperformed.
More in Motorsport terminology
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Racing line (CC BY-SA 4.0).
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