Speed Bump Spacing: How Far Apart Should Speed Bumps Be?

Parking-lot speed bumps belong 100 to 200 feet apart, per the ITE Traffic Calming Manual — 150 feet is the spec we use most often on commercial drive aisles. Residential street speed humps run 150 to 300 feet apart, per ITE and the FHWA Traffic Calming ePrimer. The reason both ranges exist: a driver shouldn't have enough room to accelerate back to pre-bump speed before hitting the next bump. Otherwise the bumps don't slow anyone down on average.

Below: the acceleration-window math, ITE spacing recommendations by site type, and how spacing plays against bump length and target speed.

Why Does Speed Bump Spacing Matter?

Three reasons drive the spacing recommendation:

• The acceleration window. A driver who slows from 25 mph to 5 mph at a bump and then accelerates back to 25 mph defeats the purpose. ITE references show drivers reach roughly 75 percent of pre-bump speed within 100 to 150 feet of acceleration on flat pavement. Spacing must close that window.
• Average corridor speed. The ITE-cited "85th percentile speed" rule for streets and "75th percentile" rule for parking lots both reference the average speed across a corridor with multiple bumps, not the spot speed at a single bump. Spacing controls the corridor average.
• Driver compliance perception. Bumps spaced too close feel punitive and encourage avoidance behavior; bumps spaced too far feel ineffective and encourage non-compliance.

The 100 to 200-foot parking-lot range and 150 to 300-foot residential-street range balance these three drivers.

What Are the ITE Spacing Recommendations?

Site Type	Recommended Spacing	Source
Parking lot drive aisle	100 to 200 feet	ITE Traffic Calming Manual chapter 3
Residential street	150 to 300 feet	ITE Traffic Calming Manual chapter 3
Collector street	250 to 500 feet	FHWA Traffic Calming ePrimer
School zone	100 to 250 feet	Oregon DOT school-zone guidance
Drive-thru lane	80 to 150 feet	ITE Parking Generation Manual
Apartment complex private street	120 to 250 feet	ITE Traffic Calming Manual

These spacings assume parabolic bump profiles per ITE Traffic Calming Manual chapter 3. Custom-profile bumps (peaked, flat-top) shift the spacing window.

How Does Spacing Interact with Bump Length?

Spacing should match bump length and target speed:

Bump Type	Length	Target Speed	Recommended Spacing
Parking-lot speed bump	1 to 3 feet	5 mph	100 to 200 feet
Residential speed hump	12 to 14 feet	15 to 20 mph	150 to 300 feet
Speed table	22 feet	25 mph	250 to 500 feet

Higher target speeds require longer spacing because the acceleration window expands. A 25 mph target speed gives drivers more room to accelerate before reaching the next device, so spacing widens to keep the corridor average in range.

For deeper detail on the bump-vs-hump-vs-table family, see speed bump dimensions. For broader code context, see speed bump standards MUTCD.

What Happens If Spacing Is Too Close?

Bumps closer than 100 feet on parking-lot drive aisles produce three problems:

• Driver frustration. Sustained sub-100-foot spacing feels punitive. Drivers route around the corridor entirely if alternate routes exist.
• Emergency vehicle delay. Fire trucks and ambulances reach response targets slowly when forced to slow every 80 feet.
• Maintenance compounding. More bumps means more chevron paint cycles, more anchor failure points, and more line-item maintenance over the asset lifespan.

Per Oregon city traffic-calming program references (Portland PBOT, Salem PW Chapter 79, Eugene EPP), 100 feet is the minimum acceptable spacing in residential settings, and 80 feet is the minimum in parking-lot contexts.

What Happens If Spacing Is Too Far?

Bumps farther apart than 200 feet on parking-lot drive aisles produce a different failure:

• Drivers reach pre-bump speed. The acceleration window closes. Corridor average climbs.
• Bumps feel like isolated obstacles. Each bump becomes a single-point annoyance rather than a corridor-wide calming pattern.
• Spot-speed compliance without average-speed compliance. Drivers slow at each bump and accelerate aggressively between them.

ITE Traffic Calming Manual chapter 3 specifically warns against spacings above 300 feet for residential streets and above 200 feet for parking lots.

How Should Property Managers Plan Bump Layout?

Three steps:

• Measure the corridor. A 600-foot drive aisle in a typical retail center fits 3 to 5 bumps at 100 to 200-foot spacing.
• Identify the entry point. Place the first bump 30 to 50 feet inside the entry, after drivers have committed to the corridor and slowed from approach speed.
• Place the last bump well before the exit. Drivers accelerating toward an exit need a final calming point. Last bump should sit 50 to 100 feet from the exit.

For broader traffic-calming strategy beyond bumps alone, see how to slow down parking lot traffic. For property managers comparing layouts across multiple sites, our Speed Bumps in Portland Metro commercial guide covers regional norms.

Worked Example: 50,000-Square-Foot Retail Center

A typical 50,000-square-foot Salem retail center has roughly 1,000 linear feet of drive aisle in three corridors. Bump layout per ITE-spec spacing:

Corridor	Length	Bumps	Spacing
Main entry to far row	400 ft	3	100 ft + 100 ft + 100 ft + 100 ft (last to exit)
Cross-aisle	350 ft	2 to 3	100 to 150 ft
Rear loading aisle	250 ft	1 to 2	100 to 250 ft

Total: 6 to 8 bumps for the property. Cojo's site survey on a March 2026 Salem retail center restripe sized the property at 7 bumps total — three in the main corridor, two in the cross-aisle, two in the rear aisle. Driver speed observations dropped from 18 mph average to 8 mph within a week of the install.

Are Spacings Different for Schools, Hospitals, or Drive-Thrus?

Slight variations apply:

• Schools: Oregon DOT school-zone guidance recommends 100 to 250-foot spacing during drop-off and pickup hours. Closer spacing is acceptable in school-zone corridors than in general commercial parking.
• Hospital campuses: ITE Traffic Calming Manual references emergency-vehicle-access constraints that often push toward speed cushions instead of bumps. When bumps are used, spacing widens to 150 to 250 feet to preserve emergency response times.
• Drive-thru lanes: ITE Parking Generation Manual references 80 to 150-foot spacing in QSR drive-thrus to control speaker-board approach speed and order-window pacing.

For marking-and-paint-cycle context, see commercial striping Portland.

Get a Site-Surveyed Layout Quote

Bump spacing depends on corridor length, target speed, and site context at your specific property. Get a custom quote and Cojo's estimator will measure your drive aisles, conduct a 75th-percentile speed observation, and recommend ITE-spec spacing before any bump goes in.

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