Alligator cracking is not a surface problem.

What you are looking at

An interconnected network of cracks forming irregular polygons, typically concentrated in the wheel paths or one defined area rather than spread evenly.

It is called alligator or fatigue cracking, and the mechanism is straightforward: the asphalt is flexing under load because there is nothing solid supporting it. Each flex propagates cracks, they intersect, and the pattern forms.

The cause is beneath the surface — a base that was too thin, never properly compacted, or that has been saturated and lost its bearing capacity.

Why filling it achieves nothing

Crack filler stops water entering through a crack in a sound surface. That is a useful job and it is not this job.

Here the surface is moving because it is unsupported. Filler in a moving crack tears open again within a season, and even if it held, the void underneath would continue growing.

Sealing over it is worse, because it hides the pattern for a year while the underlying failure accelerates.

What actually fixes it

The affected area is cut out square, back to sound material. The base underneath is excavated and inspected — if it is saturated or contaminated it comes out, and the drainage cause is identified.

New geotextile, new granular compacted in lifts, then base and surface course tied into the surrounding surface.

If alligator cracking covers more than roughly a third of the driveway, a full rebuild is generally better value than a series of patches, because the patches will be visible forever and the untreated areas are likely at a similar stage.

Catching it early

Alligator cracking rarely appears suddenly. It is usually preceded by a small area that feels slightly soft underfoot, or a place where water sits a little longer than elsewhere.

Addressing a two-square-metre area is a modest repair. Addressing a third of a driveway is a rebuild. The gap between those is a couple of seasons.