Speed bumps and speed humps for parking lots

How many speed bumps per drive aisle

Two numbers decide it: how many bumps along the aisle, and how many segments across it. Along the aisle, place one where speed builds: at the start of a long straight run, before a crosswalk or a building entry, and spaced so drivers don't speed back up between them. Closer spacing keeps speeds lower.

Across the aisle, divide the aisle width by the segment length and round up. A 24-foot two-way aisle takes four 6-foot segments; leave a gap at the curb for drainage if the bump would dam water. Add end caps where the system uses them.

Bump or hump: sizes and speeds

Speed bumps are usually 2 to 4 inches tall and 1 to 3 feet long in the direction of travel, and they slow vehicles to about walking speed. They belong in parking aisles, not on streets. Speed humps are about 3 to 4 inches tall and 12 to 14 feet long, and cars cross them at 15 to 20 mph; FHWA's traffic calming guidance covers them for local streets.

Mark every bump with paint or the molded reflective strips so drivers see it, and post a sign where traffic enters.

Installation and hardware

Modular rubber and plastic bumps are bolted down through pre-drilled holes. In asphalt, long lag spikes or spikes with washers are typical; in concrete, use wedge or sleeve anchors. Drill straight, keep segments tight end to end, and re-check anchors after the first weeks of traffic and every spring after snowplowing.

Plows catch bumps. In snow country, many owners pull removable bumps for the winter or mark them for the plow driver.

Asphalt versus concrete

Asphalt takes lag spikes but softens in summer heat, so check hold-down after hot weather. Concrete holds anchors well but needs a hammer drill and the right anchor length. Don't install over cracked or crumbling pavement: repair it first, or the anchors pull out.

Pallet counts and freight basics for speed bumps

Rubber bumps are dense and heavy, so a pallet of them ships at a low freight class but adds up in weight fast. Each product page lists weight per segment, pack size, pallet quantity and shipping class.

LTL (less-than-truckload) carriers price a pallet by its weight, its size and its freight class. Freight class runs from 50 to 500 and is set mostly by density, in pounds per cubic foot: dense, heavy pallets ship at a lower class than light, bulky ones. Your delivery address matters too. A liftgate, a residential or limited-access address, or a call-ahead appointment each add a carrier charge. Our store quotes it live at checkout from the carriers, with those options priced in.

Common speed bump mistakes

What we see go wrong:

• Putting a steep bump on a road where traffic should move at 20 mph.
• Blocking drainage across the full aisle width.
• Placing a bump in a crosswalk or across an accessible route.
• Short anchors in asphalt that loosen within a season.
• No sign or contrasting color, so drivers hit it at speed.

When speed bumps are allowed or required

No federal rule requires speed bumps in a private lot. They are an owner's choice, but fire departments and cities may limit them on fire apparatus access roads and on public streets, where a city traffic engineer decides. Check before installing on any road a fire truck uses.