What makes a good overtaking zone? The geometry of passing in motorsport

Overtaking is the single event that determines whether a race is remembered as a classic or dismissed as a procession. And yet the conditions that make overtaking possible are not random. They are geometric. They are physical. They are, to a significant extent, designed into the circuit — or designed out of it.

Understanding what makes a good overtaking zone is the most important thing a circuit designer can learn. It is also the most counterintuitive, because the answer is not "fast corners" or "wide tracks". It is something more specific, more constrained, and more interesting than that.

The physics of a pass

An overtaking move in single-seater or sports car racing follows a predictable physical sequence. The following car closes the gap to the car ahead on a straight, using the aerodynamic slipstream (reduced drag in the leading car's wake) to gain a speed advantage. At the end of the straight, both cars brake for a corner. The following car brakes later than the leading car — later enough to pull alongside or ahead before the corner entry — and claims the inside line through the braking zone and into the corner.

Every element of this sequence is a constraint on the design. The straight must be long enough for the slipstream to close a meaningful gap. The braking zone must be heavy enough — a high enough speed differential between the straight and the corner — that a late-braking lunge can gain enough distance to complete the pass. And the corner itself must be shaped so that the inside line is viable: a driver who arrives on the inside and makes the corner stick should not be spat out into a worse position on the exit.

When any one of these conditions is missing, overtaking becomes difficult or impossible. A short straight does not allow the gap to close. A light braking zone does not allow enough distance to be gained under braking. A corner where the inside line is geometrically disadvantaged — a corner that tightens sharply after the apex, for example, or one where the outside line provides a vastly better exit — punishes the overtaking driver for committing to the pass.

Straight length: the approach

The minimum straight length required for overtaking depends on the category of racing. In Formula 1, where cars produce extreme levels of aerodynamic downforce and drag, the slipstream effect is significant but the dirty air effect in corners is also severe. A straight of less than about 600 metres at F1 speeds rarely produces overtaking attempts. A straight of 800 to 1,000 metres is the range where most F1 passes happen. Straights longer than 1,200 metres — like Baku's 2.2-kilometre waterfront straight — make overtaking almost guaranteed under DRS but can feel mechanistic rather than dramatic.

In lower-downforce categories — GT3, touring cars, club racing — the slipstream is less powerful but the dirty air penalty in corners is also smaller. This means straights can be shorter and still produce passing opportunities, because the following car loses less time in the preceding corners and arrives at the braking zone with a smaller deficit to overcome.

The corner that feeds the straight matters at least as much as the straight's length. If the preceding corner is a fast, high-downforce sweeper, the following car suffers in the turbulent wake and arrives at the straight already behind. If the preceding corner is a slow, low-speed hairpin, both cars exit at similar speeds and the straight begins with a roughly equal gap. This is why Hermann Tilke's recurring pattern of a slow hairpin onto a long straight, while aesthetically repetitive, is grounded in sound overtaking physics: the slow corner equalises the cars, and the long straight allows the faster one to pull ahead.

The braking zone: where the pass happens

The braking zone is the decisive moment. A following driver who has closed the gap on the straight commits to a later braking point than the car ahead, counting on the car's remaining braking capacity to decelerate in a shorter distance. The physics of this are precise: at 300 km/h, a modern F1 car decelerates at approximately 5 to 6 g under maximum braking. Every tenth of a second of later braking translates to roughly 8 metres of distance gained. A pass requires the following car to pull alongside the leading car — roughly 5 metres — which means a braking difference of approximately 0.06 seconds is sufficient to initiate a move.

This means the braking zone does not need to be enormously long. What it needs is to be heavy — a large speed reduction in a short space. A corner that drops the speed from 300 km/h to 80 km/h in 100 metres produces a braking zone where tiny differences in commitment translate to significant position changes. A corner that drops the speed from 300 km/h to 200 km/h over the same distance produces a much less decisive braking event — the car decelerates less aggressively, the window for a late lunge is narrower, and the consequences of overshooting are smaller.

The best overtaking braking zones in motorsport share this character: they are dramatic, decisive decelerations where the physical sensation of braking is as intense as the competitive stakes. The first corner at Monza, the hairpin at Montreal, the Turn 1 braking zone at COTA, the end of Baku's straight — all are high-deceleration events where the difference between a heroic pass and a locked-up slide past the apex is measured in hundredths of a second.

The corner: making it stick

A pass is not complete when the following car pulls alongside. It is complete when the overtaking car exits the corner ahead and in a position to maintain the advantage. This means the corner geometry must allow the inside line to work — not necessarily as the optimal line, but as a viable one.

A corner with a wide entry and a tight exit favours the defender. The overtaking car arrives on the inside but has to negotiate a tightening radius that scrubs speed, while the car on the outside carries a wider, faster line through the second half of the corner and is better positioned for the exit. This geometry is sometimes called a "defensive corner" — it makes passing possible but makes completing the pass difficult.

A corner with a tight entry and a wide, opening exit favours the overtaker. The car that arrives on the inside can brake later into a tight apex and then accelerate on an opening radius where the inside line is geometrically advantageous. The car on the outside has to carry more speed through the entry (which is harder under braking) and ends up on a tighter exit radius. This geometry is the designer's friend when creating an overtaking zone — it rewards the commitment of the late brake without excessively penalising the car being overtaken.

A hairpin — a roughly 180-degree turn — is the purest overtaking corner because the geometry forces both cars through such a dramatic speed reduction that the inside line is always viable. At the apex of a hairpin both cars are traveling slowly enough that side-by-side running is physically manageable, and the exit is usually onto a straight where the overtaking car has track position. This is why hairpins produce more completed passes than any other corner type.

Track width at the braking zone

A two-car move requires enough physical space for two cars to exist side by side. This is obvious, but many circuits get it wrong by narrowing the track at exactly the point where it needs to be widest.

The ideal braking zone widens slightly on approach to the corner, giving the overtaking car space to position alongside without crowding the defender. A track that narrows into the braking zone — because of barrier placement, kerb positioning, or the geometry of the preceding straight — physically prevents the overtaking car from getting alongside, and the pass does not happen.

The apex and mid-corner also need to be wide enough for two-abreast running if the circuit is to allow passes that take more than one corner to resolve. The most memorable battles in motorsport — Hamilton and Verstappen at Copse in 2021, Leclerc and Verstappen through the Silverstone complex in 2019 — happen at corners where the track width permits two cars to race through simultaneously. A circuit that is wide at the braking zone but narrows to single-file width at the apex forces all passes to be completed before the turn-in point, which is less dramatic and less varied than a circuit that allows side-by-side racing through the corner itself.

Multiple overtaking zones: the two-opportunity minimum

A circuit with only one overtaking zone is a circuit where a single failed attempt per lap ends the contest until the next lap. This produces cautious racing — drivers know they have only one shot and take fewer risks — and it produces a situation where track position from qualifying becomes almost unassailable. A circuit needs a minimum of two genuine overtaking zones, distributed around the lap so that an attempt at one feeds naturally into an opportunity at the other.

The best circuits have three or four. Silverstone offers moves at the end of the Wellington Straight into Brooklands, at the end of the Hangar Straight into Stowe, and occasionally into Copse. Spa produces moves at the end of the Kemmel Straight into Les Combes, at the Bus Stop chicane, and sometimes at La Source. The distribution of overtaking zones means a driver who is faster but cannot pass at one point has another opportunity within 20 to 30 seconds — and the psychological knowledge that another opportunity is coming encourages more aggressive attempts at each one.

When you are designing a circuit in RaceTrackDesigner, the speed zone visualisation gives you an immediate proxy for this: look for at least two transitions from red (full speed) to green (slow corner). Each red-to-green transition represents a potential overtaking zone. If your circuit has only one, or if the transitions are all from orange to yellow (medium braking), the layout will suppress racing. Try extending a straight, adding a tighter corner at the end, or repositioning a hairpin to create a second decisive braking point.

What DRS tells us about design failure

The Drag Reduction System — the movable rear wing flap that Formula 1 introduced in 2011 to increase overtaking — is a regulatory admission that modern circuits do not produce enough natural passing opportunities. DRS works by reducing the trailing car's drag on the straight, artificially increasing the slipstream advantage and making the gap close faster than aerodynamics alone would allow.

DRS is placed on straights where overtaking should happen but does not happen reliably without assistance. Its existence is therefore a diagnostic tool: every DRS zone on every circuit is a marker of a section where the straight is too short, the braking zone is too light, or the preceding corner is too fast for the following car to stay close enough to attempt a move unaided.

A circuit designer working today should study where DRS is deployed — and ask what the circuit would need to change for DRS to be unnecessary at that point. In most cases the answer is one of the principles above: a longer straight, a heavier braking zone, a slower preceding corner, or a wider track at the commitment point. DRS solves the symptom. The design principles solve the cause.