Transverse Cracking in Asphalt: Causes, Spacing, Repair and Prevention

Transverse cracking is cracking that runs across the pavement, roughly perpendicular to the direction of traffic. On roads and highways, the most common cause is low-temperature (thermal) cracking: asphalt shrinks in cold weather, and when stress builds faster than the binder can relax, the pavement cracks across its width, often at fairly regular intervals. Other causes include reflective cracking from joints in old concrete beneath an overlay, and settlement over trenches or culverts. Transverse cracks are usually sealed to keep water out; severe ones may need patching or milling and overlaying.

Choosing a crack filler →

How to Recognize Transverse Cracks

• Run across the lane or driveway, not along it
• Often extend partly or fully across the width
• May repeat at fairly regular spacing on roads with thermal cracking
• Can widen in winter and narrow in summer
• Edges may break down over time (spalling), especially if untreated

Cracks running lengthwise are longitudinal, which our article on the crack down the middle of a driveway covers.

Common Causes

Thermal Shrinkage

Asphalt binder stiffens as it cools and ages. In very cold weather, the pavement tries to contract, and cracks form when tensile stress exceeds its strength. Stiffer, more oxidized binder cracks more easily, which is why older pavements develop more transverse cracks. Our article on asphalt binder explains how performance grades address low-temperature cracking.

Reflective Cracking

When asphalt is laid over concrete or over a cracked older asphalt layer, movement at the joints and cracks below "reflects" up through the new layer. These cracks line up with joints in the underlying pavement.

Settlement and Trenches

A crack across a driveway or road above a utility trench, culvert or pipe often points to settlement or a transition between different base conditions.

Construction Joints

A transverse joint where one day's paving stopped and the next began can open into a crack if it wasn't built and compacted well.

Severity Levels

Severity	Description	Typical response
Low	Narrow crack, sealed or unsealed, little edge damage	Seal or monitor
Medium	Wider crack, some edge breakdown or secondary cracks	Clean, rout and seal
High	Wide crack with broken edges, dips, or potholes forming	Patch, or mill and overlay

Agencies use distress manuals with specific width thresholds; these descriptions are simplified.

Repair Options

1. Crack sealing: clean the crack, optionally rout it into a reservoir, and fill it with flexible hot-pour sealant. For wide cracks, add foam backer rod first.
2. Crack filling: for less active cracks, with less expensive fillers.
3. Patching: cut out and replace badly deteriorated sections, especially where cracks have become potholes.
4. Mill and overlay: for widespread cracking, sometimes with stress-absorbing interlayers or paving fabrics to slow reflective cracking.

Our guide to backer rod for asphalt cracks explains sizing.

DIY on a Driveway

• Clean out dirt and weeds; a crack weeding hook tool helps.
• Make sure the crack is dry.
• Fill with a flexible rubberized crack filler in mild, dry weather.
• Seal cracks before sealcoating.

If a crack across the driveway is sunken or keeps reopening, the base may have settled, and a patch may be the better repair. Resist the urge to trowel filler over the top in a wide band; keeping it in the crack looks neater and holds up better under tires and snow shovels.

Prevention

• Binder grade selection: using a performance grade suited to local low temperatures.
• Avoiding overly stiff mixes: high amounts of recycled binder can stiffen a mix if not balanced.
• Adequate compaction: dense mixes age more slowly.
• Timely sealing: keeping water out limits deterioration.
• Interlayers for overlays: to slow reflective cracking over concrete.
• Well-built joints during paving.

Transverse Cracks on New Pavement

A transverse crack in a driveway or road that's only a year or two old deserves a closer look. Common explanations include a poorly compacted construction joint, settlement over a recently backfilled trench, an overlay placed on concrete with joints underneath, or a base that was soft in one area. Take photos, note the date, and contact the contractor if the work is under warranty. Early cracks over a trench may continue settling for a while, so a temporary seal and a later permanent patch is a common approach.

How Engineers Track Thermal Cracking

Pavement engineers study low-temperature cracking with lab tests that measure how binder and mix respond to cold, and use those results to pick binder grades for each climate. The low-temperature number in a performance grade (for example, the "-28" in PG 64-28) indicates roughly how cold the binder is designed to handle before it becomes prone to cracking. Colder regions typically specify binders with lower low-temperature grades. Field surveys count cracks per mile or per section to track how pavements are aging and when to schedule sealing or resurfacing.

Why Sealing Matters

Unsealed transverse cracks let water into the base. In freezing climates, the edges spall, the crack widens, and a dip forms that cars thump over. Sealing early is inexpensive compared with patching later. On roads, crews often schedule crack sealing in spring or fall, when cracks are partly open and temperatures suit the sealant. Cracks sealed in the middle of winter are at their widest, while cracks sealed in summer are narrow and may be overfilled, so timing affects how well the seal performs through a full year of expansion and contraction.

Bottom Line on Transverse Cracking

Transverse cracks run across the pavement, usually from cold-weather shrinkage, reflected joints, or settlement. Seal them early, patch where edges have broken down, and address drainage or base problems when the crack sits over a trench or keeps dipping.