Speed humps and cushions on private property: how to decide, design and maintain them
How to choose, place and maintain raised devices in parking lots and private roads
Safety Behind the Wheel Foundation built this guide from Federal Highway Administration (FHWA) traffic control standards, Occupational Safety and Health Administration (OSHA) rules, Insurance Institute for Highway Safety (IIHS) and National Highway Traffic Safety Administration (NHTSA) data, federal accessibility guidelines and published traffic calming studies. Every source is listed at the end.
What speed humps and speed cushions are
Traffic calming means changing a road or lot so drivers choose to go slower. The Insurance Institute for Highway Safety (IIHS) describes it as road changes that encourage slower speeds or less traffic, making walking and biking safer [1]. Speed humps are one example [1].
On a private site, the owner or manager picks the device, pays for it and keeps it working. On a public street, only the road agency may add one.
People use “bump” and “hump” as if they meant the same thing, and so do many research papers [2]. The devices behave differently, so learn the main types.
Comparison compiled by Safety Behind the Wheel Foundation
Speed humps, tables, cushions and bumps compared
| Device | What it is | Notes for private sites |
|---|---|---|
| Speed hump | A rounded raised strip across the lane. Studies most often describe one about 3 to 4 inches tall and 12 to 14 feet long [2]. | Slows most vehicles. Fits aisles and access roads. |
| Speed table | A flat topped hump. It can double as a raised crosswalk [6]. | Gives walkers a level path across where they must cross. |
| Speed cushion | Separate raised pads with gaps between them. Wide axle vehicles such as fire trucks can pass through the gaps [2]. | Eases emergency access, but some SUVs can straddle the pads [2]. |
| Speed bump | A shorter, steeper strip, often 1 to 3 feet long and 3 to 6 inches tall [2]. | Slows vehicles almost to a stop [2]. Suits only crawl speed spots. |
Never buy by name alone. Ask for exact measurements.
Why slow speeds matter on private sites
Private sites feel safe because speeds are low. Yet cars, trucks, walkers, children and workers share the same space, often with few signals. The National Highway Traffic Safety Administration (NHTSA) tells drivers to watch for cars entering driveways and backing in lots [8].
National numbers show what is at stake when speed rises. In 2024, speeding played a part in 29% of traffic deaths nationwide, or 11,288 deaths [7]. That year, 7,080 pedestrians died in traffic collisions [8].
Low speeds are not harmless. A study of U.S. crashes estimated that a struck pedestrian’s average risk of a severe injury reaches 10% at about 17 mph [9]. Age matters too. A 70 year old struck at a given speed faces about the same risk of death as a 30 year old struck 11.8 mph faster [9]. Those data come from 1990s collisions, so use them as a guide.
Work sites carry added risk. In 2024, 369 workers died in pedestrian incidents involving motor vehicles, up from 310 in 2023 [10].
For the hidden areas behind vehicles, read our guide on parking lot, driveway and backing safety.
What the research says humps and cushions can do
These studies were done on public streets, not private lots. Use them as a guide, then measure your own site.
Slowing is local
A study in South Korea tracked vehicle speeds near speed humps and compared pedestrian crash records [3]. Drivers began to slow about 30 meters (roughly 100 feet) before a hump. They regained their old speed within about 30 meters after it [3]. Speeds fell 18.4% on local roads and 24.0% on major roads [3]. Inside that zone, pedestrian crashes were fewer and injuries less severe than outside it [3]. A hump protects the spot where it sits, not a whole aisle.
Height decides how hard drivers slow
Researchers studied crossings near schools in BorĂĄs, Sweden. The goal was a 90th percentile speed (the speed nine in ten drivers stay under) below 30 km/h, about 19 mph. No test site met the goal [4]. After cushions were lowered from 70 mm to 55 mm (about 2.8 to 2.2 inches), that speed rose from 34 to 41 km/h (about 21 to 25 mph) [4].
Low strips and poor builds fail
In Turkey, raised thermoplastic strips (a hardened road marking material) only 4.5 cm, or about 1.8 inches, tall did not make ambulances or trucks slow down [2]. Only 7 of the 44 asphalt humps measured matched the national standard, and badly built humps can damage vehicles [2].
Which rules apply on private property
Private property does not mean “no rules.” What applies depends on where the device sits and who uses it. The Manual on Uniform Traffic Control Devices (MUTCD) is the national standard for signs, markings and signals on roads open to public travel, whether publicly or privately owned [5]. It also covers site roads that the public can use without full time access limits [5]. It does not apply to parking areas, including their driving aisles, or to private gated property closed to the public at all times [5].
Comparison compiled by Safety Behind the Wheel Foundation
Where the MUTCD applies on private property
| Where the device sits | MUTCD | What else to check |
|---|---|---|
| Site road open to the public, such as in a shopping center or campus | Applies [5] | Local permits, fire officials, accessibility limits |
| Parking area and its driving aisles | Does not apply [5] | Accessibility limits, local rules, insurer |
| Gated property closed to the public at all times | Does not apply [5] | Homeowners association (HOA) or owner rules, local code |
| Warehouse or plant aisles used by forklifts | Depends on public access [5] | Rules from the Occupational Safety and Health Administration (OSHA) for powered trucks [12] |
Where the MUTCD does not apply, a designer may still copy its look so drivers recognize the device. That is a choice, not a duty.
At a workplace, OSHA’s forklift rules require drivers to follow authorized plant speed limits [12]. OSHA also notes that forklift incidents often hurt pedestrians and bystanders [11]. Drivers must reduce speed and use the horn at cross aisles and where their view is blocked [12]. They must drive at a speed that allows a safe stop and yield to ambulances and fire trucks [12]. OSHA guidance suggests that plant managers post signs and speed limits, mark walkways and separate walkers from trucks [11]. Safety Behind the Wheel Foundation gives site managers the same advice. A hump supports these rules. It does not replace them.
Local rules matter too. Cities and counties may require permits, fire officials may review routes their trucks use, and an HOA may need a board vote. Call your local building or planning office before you spend money. A resident who wants a hump on a public street should ask the city or county traffic office for a review.
Is a hump the right fix? Steps to work through
A hump is not always the best answer. Work through these steps.
- Name the problem. Where do near misses or collisions happen, and who is at risk?
- Measure speeds. Record how fast vehicles move at the problem spot over several days. Without numbers, you cannot tell if a device helped.
- List who uses the route, from delivery trucks, buses and forklifts to bicycles, strollers and wheelchair users.
- Try easier fixes first, such as signs, striping, narrower lanes or better lighting. IIHS notes that paint and bollards can narrow lanes. It also describes a Maryland pilot where lane narrowing, outreach and enforcement cut speeding [1].
- If a raised device still fits, choose its type, height and exact location.
- Ask the people who must live with it: the fire department, maintenance and snow crews, delivery companies and your insurer.
- Install it, then measure speeds again. Adjust or remove it if it does not help.
Design details that decide whether it works
Height, length and shape
For humps, studies most often describe 3 to 4 inches high and 12 to 14 feet long [2]. A hump much lower than that may do little [2, 4]. One much taller or steeper can jolt passengers and damage vehicles [2]. Plan for the lowest and largest vehicles on your site, such as vans with ramps. Ask the supplier what ground clearance the device suits.
Where to put it
Put the device where the conflict is, such as an entrance, crossing or blind corner. Because the slowing effect lasts about 30 meters on each side [3], a long aisle may need several devices.
Swedish researchers compared cushions placed about 5 and 10 meters before a marked crossing. They suggested the longer gap, about 33 feet or two car lengths, because speeds at the crossing were somewhat lower and walkers and cyclists moved more easily [13].
Avoid a spot just past a blind curve or crest. Drivers who see the device late brake hard, and that risk grows at night and in rain or fog [2].
Drainage and snow
Water follows slopes and curbs. A hump across a lane can dam the flow and form a pond on the uphill side. Ponds hide the device and freeze in winter. Have an engineer check the slope and nearest drain and consider gaps that let water pass. Keep devices off drain inlets and utility covers.
In snow country, plow crews must know where each device sits, because edges can catch a blade. Ask whether units can be lifted out before plowing season.
Accessibility and emergency vehicle access
Wheelchairs, walkers and strollers
Federal accessibility guidelines limit changes in level along routes that people with disabilities use. A change up to 1/4 inch may be vertical. One between 1/4 and 1/2 inch must be beveled. Anything higher than 1/2 inch must be ramped [14]. A ramp can be no steeper than 1:12, which means 1 inch of rise for every 12 inches of run [14]. Accessible parking spaces and the aisles beside them must sit at the same level [14].
A hump across a path used by walkers or wheelchair users falls under these limits. Ask an accessibility specialist or your building department how they apply. Where people must cross, a flat topped table can give a level path. The MUTCD calls it a raised crosswalk and requires crosswalk markings where the manual applies [6].
Fire trucks and ambulances
Emergency vehicles use site roads too. In a controlled test in Turkey, three types of ambulances lost about 5 to 10 seconds at a single asphalt hump, depending on speed and vehicle [2]. At a pair of close humps, the loss rose to about 9 to 16 seconds [2]. Delay grew when an ambulance was stuck behind a truck at 50 km/h (about 31 mph). That cost about 55 seconds, versus about 7 behind a van [2].
The study was small and done abroad, but every hump on a crew route costs seconds. Speed cushions aim to ease this, because their gaps let wide axle vehicles pass with less slowing [2]. The authors add that one cushion design may not suit every emergency vehicle [2]. Ask your local fire department to review the plan and to say which devices it accepts on fire lanes and main routes.
Signs, markings and lighting
A hump that drivers cannot see is a hazard. Sudden braking and vehicle damage are more likely where warning signs are missing, especially at night and in fog or rain [2].
Where the MUTCD applies, speed hump markings, if used, are white markings on the hump that show its location [6]. Advance markings, if used, are eight white 12 inch lines across the lane. They grow longer and sit closer together as drivers approach [6]. The manual also allows the words BUMP or HUMP on the pavement, and warning signs [6].
Outside the manual’s reach, copying these patterns still helps drivers know what they are seeing. Paint wears away, so plan to renew it. Good lighting makes the system work after dark. Ask your engineer to plan the device, signs, markings and lights together.
Buying, installing and maintaining
Buyers include property owners, businesses, HOAs, warehouses and campuses. Common channels are industrial safety suppliers, traffic control suppliers and qualified paving or property contractors. A paving crew builds asphalt humps in place. Suppliers sell bolt down units of rubber, plastic or concrete.
Do not buy on price alone. Ask each supplier or contractor:
- What are the exact height, length and shape?
- Which vehicles and ground clearances is it made for?
- How is it fastened, and what upkeep does it need?
- Can it be lifted out for plowing or repairs?
Also ask your insurer and your own attorney whether the change affects your coverage or duties.
Devices wear and loosen. This routine keeps them safe.
Limits, common mistakes and what you can do
A hump slows vehicles at one spot, and drivers speed up soon after [3]. Some SUVs can pass cushions without slowing, and drivers may aim for the middle pad of a three pad set [2]. A hump also does not remove blind zones or separate walkers from vehicles. See our guide on pedestrian safety for drivers for scanning habits.
Common mistakes include buying by name or price, expecting one device to slow a whole aisle, ignoring drainage, plowing or fire access, and never measuring speeds before and after.
What drivers, workers and neighbors can do:
- Drivers: slow down before the device, not on it. Watch for people stepping out.
- Forklift operators: follow plant speed limits and slow down at cross aisles and blocked views [12].
- Employers and managers: post the site speed limit, train staff and measure results.
- Residents and tenants: ask the property manager or HOA board for a speed review. Bring dates, places and notes about where people walk. Never install a device yourself.
Frequently asked questions
Is a speed bump the same as a speed hump?
No, though people often swap the words. A hump is longer and gentler. A bump is shorter and steeper, and it slows a vehicle almost to a stop [2]. Because the names are used loosely, ask any supplier for exact measurements.
Are speed cushions better than humps?
Cushions let wide axle vehicles, such as fire trucks, pass with less slowing [2]. The Turkish study’s authors write that cushions and humps of the same height and length slow traffic in a similar way [2]. But some SUVs can pass cushions without slowing [2]. Ask your fire department which type it accepts.
How many humps does a long aisle need?
An engineer decides this from speed counts. In the Korean study, drivers slowed only within about 30 meters (roughly 100 feet) of a hump [3]. A long aisle may need several devices, and a short one may need one. More devices also mean more noise, cost and delay [2].
Can a hump cross an accessible route?
It can fall under federal accessibility limits. Changes in level above 1/2 inch must be ramped, and ramps can be no steeper than 1:12 [14]. Have a specialist review the plan before you build.
Are painted lines or low strips enough?
Flat paint does not lift a vehicle, though IIHS notes it can help narrow lanes [1]. Raised thermoplastic strips only 1.8 inches tall did not slow ambulances or trucks in the Turkish test [2]. Use paint as part of a plan, not as a stand in for a proper device when speeds are a real problem.
The bottom line
Recommendation from Safety Behind the Wheel Foundation
Safety Behind the Wheel Foundation recommends measuring speeds before and after any speed hump or cushion goes in, and involving the fire department from the start. A speed hump or cushion is a tool, not a cure. It works when it matches a measured problem, has a sound height and length, and sits where the conflict is. It fails when it is too low, buried in snow or placed across a wheelchair route or fire lane.
Start with speed counts. Bring in a qualified traffic engineer, involve the fire department early and measure again after installation. Slower speeds protect the people around your site.
Related articles
Sources and further reading
- 1Insurance Institute for Highway Safety (IIHS). Speed. Updated July 2026. iihs.org/research-areas/speed
- 2Öz E, Küçükkelepçe O, Kurt O, Çavuş AC. Effect of Speed Humps on Ambulance Delay. Cureus, published January 12, 2023 (PubMed record). Data year: field tests after October 2022 in Adıyaman, Turkey. pubmed.ncbi.nlm.nih.gov/36788894
- 3Yeo J, Lee J, Cho J, Kim D-K, Jang K. Effects of speed humps on vehicle speed and pedestrian crashes in South Korea. Journal of Safety Research, published August 2020 (PubMed record). Data year: not stated in the abstract (South Korean speed and crash records). pubmed.ncbi.nlm.nih.gov/33334495
- 4Johansson C, Leden L. Short-term effects of countermeasures for improved safety and mobility at marked pedestrian crosswalks in Borås, Sweden. Accident Analysis and Prevention, published online November 2006 (PubMed record). Data year: not stated in the abstract (short-term study after Sweden’s May 2000 crosswalk rule change). pubmed.ncbi.nlm.nih.gov/17129567
- 5Federal Highway Administration (FHWA). Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition, Part 1: General, Sections 1B.01 and 1C.02. Published December 2023. mutcd.fhwa.dot.gov/pdfs/11th_Edition/part1.pdf
- 6Federal Highway Administration (FHWA). Manual on Uniform Traffic Control Devices (MUTCD), 11th Edition, Part 3: Markings, Sections 3B.29 and 3B.30. Published December 2023. mutcd.fhwa.dot.gov/pdfs/11th_Edition/part3.pdf
- 7National Highway Traffic Safety Administration (NHTSA). Speeding. Last-updated date not shown on the page; read October 2026. Data year: 2024. nhtsa.gov/risky-driving/speeding
- 8National Highway Traffic Safety Administration (NHTSA). Pedestrian Safety. Last-updated date not shown on the page; read October 2026. Data year: 2024. nhtsa.gov/road-safety/pedestrian-safety
- 9Tefft BC. Impact speed and a pedestrian’s risk of severe injury or death. Accident Analysis and Prevention, published online August 2012 (PubMed record). Data year: crashes from 1994-1998, with risks standardized to 2007-2009. pubmed.ncbi.nlm.nih.gov/22935347
- 10U.S. Bureau of Labor Statistics (BLS). Census of Fatal Occupational Injuries Summary, 2024. Released February 19, 2026. Data year: 2024 (with 2023 comparison). bls.gov/news.release/cfoi.nr0.htm
- 11Occupational Safety and Health Administration (OSHA). eTool: Powered Industrial Trucks (Forklift) – Understanding the Workplace – Pedestrian Traffic. Date not shown on the page; read October 2026. osha.gov/…/pedestrian-traffic
- 12Occupational Safety and Health Administration (OSHA), via the Electronic Code of Federal Regulations. 29 CFR 1910.178, Powered industrial trucks, paragraph (n) Traveling. Last amended November 18, 2016; read October 2026. ecfr.gov/…/section-1910.178
- 13Johansson C, Rosander P, Leden L. Distance between speed humps and pedestrian crossings: does it matter? Accident Analysis and Prevention, published online May 2011 (PubMed record). Data year: not stated in the abstract (three Swedish test sites). pubmed.ncbi.nlm.nih.gov/21658513
- 14U.S. Access Board (Architectural and Transportation Barriers Compliance Board), via the Electronic Code of Federal Regulations. 36 CFR Part 1191, Appendix D: Technical, sections 303, 405 and 502. Current text read October 2026. ecfr.gov/…/appendix-Appendix%20D%20to%20Part%201191
This article reflects the safety priorities of traffic calming and safe site design on private property. It is general education, not legal, insurance or professional design advice. Rules change, so verify details with official sources. For your own site, contact a licensed traffic or civil engineering firm, your local building, planning and fire officials, your property insurer and an accessibility consultant. Residents who want a change on a public street should contact their city or county traffic office. Reviewed October 2026.
Cite this article: Safety Behind the Wheel Foundation. “Speed humps and cushions on private property: how to decide, design and maintain them.” drivewithcare.org, https://drivewithcare.org/private-site-speed-humps-speed-cushions-guide/. Reviewed October 2026.
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