Speed Bump Dimensions: How Tall, Wide & Long They Are

A standard parking-lot speed bump in 2026 measures 3 to 4 inches tall at centerline, 1 to 3 feet long in the direction of travel, and 8 to 24 feet across the lane depending on drive-aisle width. The ITE Traffic Calming Manual treats those as the canonical numbers for parking-lot bumps; the FHWA Traffic Calming ePrimer backs the same spec.

Below: the three dimensions that define every speed bump, the "width" versus "length" mix-up that trips up most buyers, and how lane coverage drives the number of sections you need.

What Are the Three Dimensions of a Speed Bump?

Three dimensions describe every speed bump:

• Height. The vertical measurement from existing pavement grade to the top of the bump at centerline. Standard is 3 to 4 inches.
• Length. The horizontal measurement in the direction of travel — how far across the bump a tire rolls. Standard parking-lot bump is 1 to 3 feet long. Speed humps run 12 to 14 feet long; speed tables run 22 feet long. Length is what distinguishes a bump from a hump from a table.
• Width (lane span). The horizontal measurement perpendicular to travel — how far across the lane the bump extends. ITE recommends covering full lane width, typically 12 to 14 feet for single-lane drive aisles and 22 to 26 feet for two-way drive aisles.

Manufacturers and buyers often use "width" and "length" interchangeably, which produces confusion. This guide uses ITE's convention: length runs in the direction of travel, width spans the lane.

What Are the Standard Speed Bump Dimensions in 2026?

Dimension	Standard Range	Source
Height (centerline)	3 to 4 inches	ITE Traffic Calming Manual chapter 3
Length (in direction of travel)	1 to 3 feet	ITE Traffic Calming Manual chapter 3
Width (lane span) — single lane	12 to 14 feet	ITE Parking Generation Manual
Width (lane span) — two-way drive aisle	22 to 26 feet	ITE Parking Generation Manual
Width (lane span) — wide entrance approach	24 to 30 feet	ITE Parking Generation Manual

Per the FHWA Traffic Calming ePrimer, height-to-length ratio determines target speed: a 3-inch height with 1-foot length produces a 5 mph parking-lot bump; a 3-inch height with 12-foot length produces a 15 to 20 mph residential-street speed hump.

What Section Lengths Are Available?

Manufacturers sell modular rubber and plastic bump sections in fixed lengths that buyers link end-to-end to span the lane:

Section Length	Typical Use	Connector Required
2-foot mid-section	Trim piece for odd lane widths	Yes
4-foot section	Driveways, narrow drive lanes	Optional
6-foot section	Single-lane parking aisles	Optional
10-foot section	Two-way drive aisles (paired with mid-section or end caps)	Yes
12-foot section	Wider drive lanes	Yes

A 22-foot two-way drive aisle is most efficiently covered with two 10-foot sections plus a 2-foot mid-section. A 24-foot drive aisle uses two 12-foot sections.

How Does Height Affect the Bump's Behavior?

ITE references and Cojo field experience show that the 3 to 4-inch height range is the engineered sweet spot:

• Below 3 inches. Drivers do not slow meaningfully. The bump becomes a visual cue without traffic-calming effect.
• 3 inches. Optimal for low-impact passenger vehicles and most parking-lot scenarios.
• 4 inches. Slightly more aggressive; can damage low-clearance vehicles if hit at over 10 mph.
• Above 4 inches. Damages cars at parking-lot speeds. SAE-cited engineering studies show oil-pan and exhaust contact at heights above 4.5 inches with sub-12-foot length.

The FHWA Traffic Calming ePrimer specifically warns against "creative" custom heights that fall outside the 3 to 4-inch window. Insurance liability rises sharply for non-standard dimensions.

For deeper detail on height alone, see how tall are speed bumps.

How Does Length Affect Target Speed?

Length is what distinguishes the family of vertical-deflection devices:

Length	Device	Target Speed
1 to 3 feet	Speed bump	5 mph (parking lot)
12 to 14 feet	Speed hump	15 to 20 mph (residential street)
22 feet	Speed table	25 mph (collector street)

ITE Traffic Calming Manual chapter 3 documents these length-to-speed relationships. The FHWA Traffic Calming ePrimer cross-references the same data.

For deeper detail on length alone, see how wide are speed bumps (which addresses the buyer-confused "width" question).

How Wide Should the Bump Span the Lane?

The Institute of Transportation Engineers Parking Generation Manual references typical commercial drive-aisle widths:

• Single-lane drive aisle (one-way): 12 to 14 feet
• Two-way drive aisle: 22 to 26 feet
• Wide entrance approach: 24 to 30 feet

ITE recommends covering full lane width with continuous bump to prevent drivers from steering around. Gaps between section ends invite tire avoidance and defeat the bump's purpose.

For Portland Metro property managers comparing lane geometries across multiple sites, our Speed Bumps in Portland Metro commercial guide covers regional drive-aisle norms.

What Cross-Section Profile Should the Bump Have?

ITE Traffic Calming Manual chapter 3 specifies a parabolic cross-section: smooth rise from existing pavement grade to centerline height, then smooth fall back to grade. Three profile shapes appear in practice:

• Parabolic (recommended). Smooth curve. Comfortable for compliant drivers; uncomfortable for speeders.
• Flat-top with ramp transitions. Used on speed tables, not on speed bumps. Flat-top on a 1 to 3-foot length is structurally unstable.
• Peaked / triangular. Damages vehicle suspension at any speed. Not recommended; not compliant with ITE references.

Asphalt-poured bumps shape the parabolic profile during the screed step. Modular rubber and plastic bumps come pre-formed in the parabolic profile.

How Should Property Managers Verify Dimensions?

Three checks before signing a quote:

• Height at centerline: measure 3 to 4 inches against a level. Anything outside that window is non-standard.
• Length in direction of travel: measure from leading edge to trailing edge. Confirm 1 to 3 feet for parking-lot bumps; 12 to 14 feet for speed humps.
• Width across the lane: confirm full lane coverage with no gap that allows steering-around.

On a 14,000-square-foot Salem retail center we restriped in March 2026, the owner inherited four speed bumps from a previous install that measured 4.5 inches tall at centerline. Vehicle damage complaints had run for two years. We replaced all four with ITE-spec 3.5-inch bumps; complaints stopped.

For the broader code-and-spec context behind these dimensions, see speed bump standards MUTCD. For broader paving-and-marking spec context, our concrete vs asphalt striping guide covers the cross-silo paint-and-marking layer.

Get a Site-Surveyed Speed Bump Quote

Dimensional spec depends on lane geometry, traffic load, and target speed at your site. Get a custom quote and Cojo's commercial estimator will measure your drive aisles, recommend section pairings that cover the full lane, and verify ITE-compliant cross-section before any anchor goes in.

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