Parts of a Driveway – Apron, Flares, Joints and Base

All 9 parts on the diagram

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From above 7

Apron The part of the driveway nearest the street. It lies between the street and the sidewalk. Contractors also call it the approach.
Flares The sloped sides of the driveway ramp. They sit where it rises from the street to the sidewalk.
Curb The raised edge along the street. It is lowered where the driveway crosses; that gap is a curb cut. British English says dropped curb or crossover.
Sidewalk Runs straight over the driveway. Cars cross the sidewalk on the driveway to reach the street.
Slab The driveway itself, here a concrete slab. Driveways are also made of asphalt, gravel or paving blocks.
Control joints Grooves tooled or sawn into the slab. Cracks tend to form along them and not at random elsewhere. Also called contraction joints.
Expansion joint Lets the slabs move without cracking each other. A strip of soft filler where the slab meets the sidewalk or the garage floor. Also called an isolation joint.

Cut through 2

Subbase A layer of material laid on the subgrade, under the slab. Not every driveway has one.
Subgrade The native soil under the driveway, compacted before paving. Even support from it keeps the slab from settling and cracking.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two independent sources use it: Wikipedia, text only (Driveway, https://en.wikipedia.org/wiki/Driveway; Curb cut, https://en.wikipedia.org/wiki/Curb_cut; Expansion joint, https://en.wikipedia.org/wiki/Expansion_joint; Subgrade, https://en.wikipedia.org/wiki/Subgrade; Base course, https://en.wikipedia.org/wiki/Base_course; Concrete slab, https://en.wikipedia.org/wiki/Concrete_slab); the US Federal Highway Administration, Designing Sidewalks and Trails for Access, Part II, chapter 5, Driveway Crossings, https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/sidewalk2/sidewalks205.cfm (driveway crossing, flare, curb, sidewalk, ramp); and a concrete trade publisher's two driveway guides, https://www.concretenetwork.com/concrete/concrete_driveways/basics.html and https://www.concretenetwork.com/concrete/concrete_driveways/planning-tips.html (apron, approach, curb, sidewalk, driveway slab, control joints, isolation and expansion joints, subgrade, subbase). Hints and detail lines are in our own words. Licence: own work

The drawing: Drawn for this site on 2026-10-05 by script from our own geometry: the driveway, the street and the house as one small 3-D model in a perspective view from above the street side, and a cut block of the slab and the ground under it. Nothing traced. The form of the curb, the ramp and its flares was checked by eye against figures 5-2 and 5-4 of the US Federal Highway Administration's Designing Sidewalks and Trails for Access, Part II, chapter 5 (a US government work). Not to scale and not any city's standard drawing. Licence: own work

How it works

The first drawing looks down on a house driveway, from the garage to the street. The second cuts through the slab to show the layers under it.

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From the street to the garage

The curb is lowered where the driveway meets the street. From there the apron rises to the sidewalk, with a flare, a sloped wedge, on each side. The sidewalk runs straight across. Beyond it the slab runs up to the garage. Control joints are cut into the slab so that cracks form along them and not at random. Where the slab meets the sidewalk or the garage floor there is an expansion joint, a strip of filler that lets each slab move. Underneath, the slab rests on a subbase, where there is one, and that rests on the subgrade, the compacted soil.

A driveway should slope toward the street and away from the house and garage, so water runs off it.
The street end goes by several names: apron, approach and driveway crossing.

Questions and answers

What are the parts of a driveway called?

From the street in: the curb, which is lowered for the driveway; the apron and its flares; the sidewalk crossing; and the slab, divided by control joints, with an expansion joint where it meets other paving. Under it are the subbase and the subgrade.

What is the end of a driveway at the street called?

The apron, also called the approach. It is the part of the driveway nearest the street, and the opening in the curb that lets cars reach it is a curb cut.

What are the lines in a concrete driveway for?

They are control joints, grooves tooled or sawn into the slab. Concrete tends to crack as it ages and shrinks, and the cracks form along the grooves, out of sight, and not at random across the slab.

What is under a driveway?

The subgrade, which is the native soil, compacted, and often a subbase, a layer of material laid on top of it. Even support from below keeps the slab from settling and cracking.