Nobody can enforce a limit on this road
The drawing note says 20 mph and there is no such thing on this job. An estate road that has never been adopted carries no statutory limit, so the roundel at the entrance is advice, enforcement is whatever the management company wrote into the leases, and the only thing on site that will genuinely slow a car is a lump of asphalt across its wheel path. That single fact reorders the price. On an adopted scheme the signs carry the legal weight and the humps support them; here the humps do the whole job and the signs are the part that makes it look official to a residents' association.
It also means nobody downstream is going to check your work against a specification. There is no highway authority to reject a hump that is 20 mm low or a line that reads at half the retroreflectivity it should. The client sees a finished road, signs a certificate, and the failure shows up eighteen months later as a complaint about people speeding past the school bus stop, which is exactly the outcome the works were bought to prevent. Price it as though somebody were checking, because the only person who will ever audit it is you, in year two, at your own cost.
Three purchases sit under the one heading and they share nothing except a chainage. The humps are asphalt bought by volume and laid by hand from a hot box, or they are moulded modules bought by the piece and bolted down. The sign foundations are a concrete quantity that turns out to be a labour and delivery question long before it is a materials one. The markings and their beads are paint by the litre and glass by the kilogram, from a supplier who will send you a pail and a bag and charge more for the carriage than for either. Quantify them as three jobs, because that is how they will be delivered and how they will go wrong.
What a laid speed bump is made of, in the direction of travel
- Drop-on glass beads — bought by mass against the marked area rather than against the paint volume, and useless once they are damp in the bag Roadway Striping Retroreflective Drop-On Bead Calculator
- Crest and approach marking — the daytime half of the visibility, worn off the crest first because every tyre on the road tracks the same two lines Line Striping Paint Calculator
- Moulded asphalt body — the item the whole scheme rests on, and the only one whose quantity depends on a cross-section shape rather than on a footprint Speed Bump/Hump Material Volume Calculator
- Bond coat — a thin emulsion over the swept and dried footprint, without which the hump debonds at its feather edge in the first hot spell Asphalt Tack Coat Calculator
- Existing surface course — the layer you core or at least scrape before pricing, because a hump laid on a failing surface takes the surface with it
Half a cubic metre of asphalt, six times over
The volume of a hump is decided by its profile, and there are only about four profiles in circulation. Everything else — length across the carriageway, height at the crown — is a dimension you can read off the drawing or set with a template. The profile is the part that turns those dimensions into a tonnage, and it is the part most estimators skip by multiplying length by width by height and adding a bit.
That product is the rectangular block the hump is carved out of, and the fraction of it a real hump actually occupies comes straight out of geometry rather than out of any standard. A parabolic crown fills exactly two-thirds of its bounding box, which is where the 0.67 that sits in the calculator's shape factor field comes from; a shallow circular arc is close enough to a parabola at these heights that the same figure serves. A sinusoidal profile fills 2/π of the box, about 0.64, so it is a touch leaner. A flat-topped table is the odd one out and much fuller: on a five-metre table with one-metre ramps each side the flat portion is three metres of full height and the two ramps average half, giving four metre-heights out of five, or 0.8.
Take a real estate road: six round-top bumps, each 5.5 m across a 6.0 m carriageway so a 250 mm gap stays open in each channel, 600 mm in the direction of travel and 75 mm at the crown. At 0.67 that is 0.166 m³ a bump and 0.995 m³ for the six. Multiply the box out instead, as though a hump were a kerb, and you get 1.49 m³ — half as much again, and the difference is a hot box you paid for and tipped. At a compacted density somewhere between 2,300 and 2,450 kg/m³, which is a figure to take from the mix design and not from an article, one cubic metre is roughly 2.3 to 2.45 tonnes of material for the entire scheme. No asphalt plant sells that as a delivery. You are buying a part load, hiring hot boxes, or negotiating a tail-end drop off somebody else's surfacing job on the same estate, and that logistics answer changes the price far more than the shape factor does.
The arithmetic itself scales fine — the two-thirds factor does not care how long the hump is — but the calculator's travel-direction field stops at 0.9 m, and that boundary is worth respecting for a reason beyond the input mask. At 3.7 m in the direction of travel, the twelve-foot round-top hump the ITE recommended practice describes, you are no longer laying a moulded object on a road with a rake and a template. You are laying a short length of road at a different level, with a paver or a screed, and the quantity that actually gets ordered is a tonnage against a surfaced area at an average thickness. Price it that way and it behaves; price it as a moulded cross-section and the waste allowance will be nonsense. The modular route — rubber or recycled-polymer sections bolted through the surface course — leaves volume behind entirely and becomes a count of modules, end caps and fixings, plus a note on the quotation that the fixings need a sound surface to bite into and that the estate road may not have one.
| Profile | Dimension in the direction of travel | Fraction of length × width × height, and why |
|---|---|---|
| Round-top bump, car-park type | 300–900 mm | ≈0.67 — the area under a parabola is two-thirds of its box |
| Sinusoidal bump | similar footprint, gentler entry | 2/π ≈ 0.64 — leaner than the parabola by about five per cent |
| Round-top hump, twelve-foot pattern | 3.7 m | ≈0.67 still, but at this size quantify as paved area × average thickness |
| Speed table with 1:10 ramps | 5–7 m including ramps | flat length plus half each ramp, over the whole length — 0.8 on a 5 m table |
| Bolt-down modular sections | sold by the section | no volume at all; count modules, end caps and fixings |
Put in the width across the carriageway, the travel-direction dimension and the crown height, then set the shape factor from the profile on the drawing rather than leaving it at the default — 0.64, 0.67 and 0.8 are three different orders on the same job.
The length of the speed bump measured across the road width.
The width of the speed bump in the direction of vehicle travel.
The maximum height of the speed bump at its crown.
A factor that scales down the full rectangular block volume to approximate the actual rounded cross-section.
Speed bump material needed
0.0729 yd³
The shape factor approximates a rounded or parabolic hump cross-section — actual material needed varies with the specific speed bump profile (circular, parabolic, or sinusoidal) specified by your project.
They open the calculator with your figures already in it
Speed Bump/Hump Material Volume Calculator: 0.0729 yd³ — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Describes the finished shape, not the mix that goes down. Hot asphalt is placed loose and compacts roughly a fifth thinner, so the quantity laid exceeds the in-place volume shown — build to the calculated figure and the bump finishes low, and a low bump slows nobody down.
- Asphalt is bought by mass, and this is a very small volume. At around 2.3 t/m³ (145 lb/ft³) compacted, a typical bump is a couple of hundred kilos of mix, well under any plant's minimum load — what actually gets paid for is the minimum ticket and the truck, not the volume, which is why bumps are worth batching with other paving on the same day.
- For a rubber bump, volume is the wrong unit altogether. Modular rubber comes as sections of fixed length with end caps, so the order is a section count across the road width plus the anchor bolts into the pavement — a cubic-metre figure converts to none of it.
Water and the vehicles that still have to get through
A full-width hump on a road with kerb and channel is a dam, and it is the objection that arrives after the concrete has gone in. Surface water on an estate road runs in the channel to the gullies, and a hump taken hard against both kerbs stops that flow dead. Upstream of each hump you get a standing pool the width of the channel, which freezes into a sheet exactly where a driver is braking, breaks the surface up along the joint over a couple of winters, and gives residents something legitimate to complain about that has nothing to do with speed.
The usual answer is a gap in each channel, narrow enough that a car wheel cannot use it as a bypass and wide enough to pass the flow that reaches it. Set that dimension against the drainage design rather than by eye: if the gap will not pass the flow, the hump has to move to sit immediately downstream of a gully instead, and moving one hump moves the spacing of all of them. Check the road's crossfall while you are at it, because a hump laid to a level template across a road with a crown ends up with a crown of its own that the drawing never showed, and the two channel gaps end up at different depths.
Then there is everything that has to keep driving over it. Refuse vehicles come weekly and their wheelbase and overhang are the contractor's own figures, not a published standard; an appliance turning into the estate is governed by the fire service's access requirements, which in the United States are set out in the International Fire Code, Appendix D, Fire Apparatus Access Roads, and elsewhere by the equivalent access provisions the building control body applies. Ambulance ride quality is a real and recurring objection to full-width humps and it does not go away by being argued with. Where those pressures bite, speed cushions are the alternative that answers all three at once: a pair of raised pads narrower than a wide axle, leaving a clear channel each side and a track a fire appliance can straddle while a car cannot. They are the same volume arithmetic, run twice on a smaller footprint, and they consume more marking than a full-width hump does because every pad needs its own outline.
A hole for every sign, and the load charge behind it
A sign post foundation is not carrying anything. The post and panel together weigh very little, and the concrete around the post exists to stop the whole assembly rotating in the ground when the wind pushes on the panel. That is a lateral problem, resolved by mobilising passive pressure in the soil against the side of the shaft, which is why the depth of the hole matters far more than its diameter and why doubling the diameter buys much less than most people expect. Somewhere in the same decision sits the local frost line, taken from the adopted building code for the jurisdiction, because a foundation founded above it will heave a post out of plumb regardless of how well it resists wind.
The load itself comes from panel area, exposure height and a design wind pressure, and none of those are worth guessing. Take a 1200 × 900 panel: 1.08 m² of area with its centroid perhaps 2.1 m above ground. At a design pressure of 1 kPa — a placeholder to show the shape of the calculation, not a value for your site — that is 1.08 kN of force and 2.3 kNm at the base of the post, on a single support. The pressure for a real site comes from ASCE/SEI 7 Minimum Design Loads and Associated Criteria for Buildings and Other Structures, or from BS EN 1991-1-4, Eurocode 1: Actions on structures, Part 1-4: General actions — Wind actions. The support that has to carry it is covered by the AASHTO LRFD Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals, and in Europe by BS EN 12899-1, Fixed, vertical road traffic signs, Part 1: Fixed signs, which treats the panel, the post and the fixings as one system with a declared performance. On a low-speed private road the breakaway provisions of the AASHTO Roadside Design Guide will usually not apply, but a rigid post standing where a vehicle can reach it is a conversation worth having with the client's insurer before it is a conversation about a claim.
The estimating twist arrives once you count the holes. Fourteen signs on this estate — two advisory roundels at the entrance, six hump warnings, four priority signs at the internal junctions and two no-through-road plates — each on a 300 mm shaft 900 mm deep. That is π × 0.15² × 0.9, or 0.0636 m³ apiece and 0.891 m³ for all fourteen. Add ten per cent because an auger in reinstated ground does not give you a clean cylinder and you are at 0.98 m³. Call it one cubic metre for a whole road's worth of signage.
One cubic metre is the awkward number. It is comfortably below the threshold at which every ready-mix plant applies a part-load charge, and the delivery is governed by ASTM C94, Standard Specification for Ready-Mixed Concrete, whose limits on elapsed time and drum revolutions before discharge decide whether one truck can serve fourteen holes spread over 420 m of road with the crew you actually have. Against that, a cubic metre in bags is roughly fifty-nine bags at the 0.6 ft³ (0.017 m³) yield an 80 lb bag is sold on, or about eighty-three 25 kg bags — read the yield off the bag, because it varies by product — and that is a full day of mixing for two people. The crossover between the two sits right around this quantity, and it is a labour decision dressed up as a materials one. Worth pricing before you assume either. The third route removes the concrete altogether: driven or sleeved posts, where the ground allows, turn fourteen pours into fourteen hammer blows and a torque wrench, at the cost of a fixing that is much less forgiving of a post being struck.
- Fix the sign positions on the ground first and check them against the hump chainages, because a warning sign that ends up behind a hump is a sign nobody reads.
- Have the services located and marked before an auger turns — HSE guidance HSG47, Avoiding Danger from Underground Services, covers the method — because a verge carries the lighting main at exactly the depth the shaft wants.
- Drill one hole early, look at the spoil, and revisit both the volume and the depth if what comes out is not what the site investigation described.
- Set the post plumb in two directions, brace it, and check plumb again once the concrete is placed and before it stiffens — a post that has moved 5 mm at the base is visibly leaning at panel height.
- Cap the shaft below finished level and reinstate over it in verge or surfacing, so the concrete is not a trip hazard and not the first thing a mower finds.
- Record which panel went on which post, because the schedule and the as-built rarely agree by the end of a job.
Diameter and depth give the theoretical cylinder for one shaft; multiply by the sign count yourself, add the allowance for hole irregularity, and only then decide whether the answer is a truck or a pallet of bags.
The diameter of the drilled cylindrical foundation.
How deep the foundation is drilled below grade.
Foundation concrete volume
0.08367 yd³
They open the calculator with your figures already in it
Traffic Sign Post Foundation Concrete Calculator: 0.0837 yd³ — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Alongside a road, a sign foundation is a safety item before it is a concrete item. Posts inside the clear zone are required to break away or yield on impact, which puts rules on how far the foundation may finish above grade and on the slip base or frangible coupling that sits on top of it. A rigid post grouted into a plug standing proud of the ground is a fixed hazard regardless of how correct its volume is.
- The cylinder includes the space the post occupies. A 100 mm (4 in) post through a 300 mm (12 in) hole displaces roughly a tenth of the concrete shown, which quietly cancels part of any allowance added for an oversized auger cut — worth knowing when one truck is servicing a run of foundations that are each a fraction of a cubic metre.
Ten kilos of glass decides whether the road exists at night
Paint on its own is a daytime product. At night, headlights strike a bare painted line at a very shallow angle and almost nothing comes back to the driver's eye, which is why a freshly lined road can look immaculate at four in the afternoon and disappear at nine. The glass fixes that: spheres dropped into the wet film sit partly embedded, refract the beam, bounce it off the paint behind them and refract it back out along the line it came in on. The widely quoted optimum embedment is somewhere around half to sixty per cent of the bead diameter — too shallow and the beads are swept away by the first week of traffic, too deep and the light never gets back out — and that is a property of how the beads meet the wet paint, not of how many you bought.
Quantity, though, is bought by mass against the marked area, and this is where estimates go wrong. Beads are not proportional to paint volume; they are proportional to the surface the paint covers, because they are broadcast across it. The rate is an areal density in kilograms per square metre of line, it comes from the project specification, and the gradation it assumes is defined in AASHTO M247, Standard Specification for Glass Beads Used in Pavement Markings, or in BS EN 1423, Road marking materials — Drop on materials — Glass beads, antiskid aggregates and mixtures of the two. Sieve analysis for those gradations runs to ASTM D1214, Standard Test Method for Sieve Analysis of Glass Spheres. Coarser beads sit proud and hold a wet-night reading better; fine ones give a brighter dry line and vanish in rain. That trade is a specification decision, and the two answers need different masses of glass on the same road.
Work the estate road through it. There are 380 m of 100 mm longitudinal line, which is 38 m² of marked surface, and six hump crests with roughly 2.9 m² of triangles apiece, another 17.4 m². Total 55.4 m². At 0.18 kg/m² that is 9.97 kg of beads — one 25 kg bag, with more than half of it left over. The paint for the same area at a 380 micron wet film is about 21 litres. The entire night-time performance of a 420 m road is ten kilos of glass and a pail of paint, which is precisely why it is the item most often left off a quotation altogether, and precisely why leaving it off is the most visible failure on the job.
Because the quantity is small, the risks move somewhere else. Beads must be dry: AASHTO M247 covers moisture resistance and flow for exactly this reason, and a bag left open in a damp van clogs the gun, comes out in clumps and lands as bare patches you will not see until dark. The drop has to happen while the paint is still wet, which on a walk-behind machine means the bead gun running off the same trigger a hand's breadth behind the paint gun, and on a hand-lined job means a second person following immediately with a hopper. A minute's delay and the film has skinned; the beads bounce off and you have paid for glass that is now lying in the gutter. Note also that the calculator's line width field is labelled in metres and stays in metres whichever unit system the rest of the page is in — 0.1 for a 100 mm line, as the label says — and that its breakdown prints the marked area back to you, the quickest check that you typed what you meant.
Handover is where the number becomes checkable. Retroreflectivity is reported as R_L in millicandelas per square metre per lux, measured at the 30 m geometry with a portable retroreflectometer under ASTM E1710, Standard Test Method for Measurement of Retroreflective Pavement Marking Materials with CEN-Prescribed Geometry Using a Portable Retroreflectometer. BS EN 1436, Road marking materials — Road marking performance for road users, sets out separate performance classes for dry, wet and rainy conditions, which is how a line that passes a dry reading can still be useless in rain. The MUTCD's minimum maintained retroreflectivity provisions for longitudinal pavement markings give the public-road benchmark; a private estate is outside them, but they are the only number anyone will cite in an argument, so take a reading on the day you finish and file it.
| What you see after dark | Mechanism | Where it is settled |
|---|---|---|
| A new line reads dark from a car | Beads dropped onto skinned paint and bounced off | The paint data sheet's wet time, and the gun spacing on the machine |
| Bright for a month, then dull | Beads embedded too shallow and swept out by traffic | Wet film thickness against bead size — a paint decision, not a bead one |
| Never bright, even when new | Beads sunk below half their diameter in too thick a film | The same pairing, from the other direction |
| Bare patches along an otherwise good line | Damp beads clumping in the gun | AASHTO M247 moisture and flow requirements, plus how the bag was stored |
| Fine in the dry, gone in rain | Fine gradation with no coarse or wet-night bead | The specified gradation, and the wet class in BS EN 1436 |
| The crest of every hump worn bare first | Every tyre on the road tracks the same two lines over the same 600 mm | Maintenance interval, agreed at handover rather than discovered |
Give it the total run, the line width in metres and the rate the specification names, then run it again for the transverse markings converted to an equivalent run — the two answers add up to one bag more often than anyone expects.
The total length of striping to receive drop-on beads.
The painted width of the striped line.
The mass of glass beads applied per unit of striped line area.
Retroreflective bead material needed
20.2 lb
Bead application rate varies by bead gradation (Type I/II/III per AASHTO M247) and target retroreflectivity level — confirm the rate for your specific project specification rather than assuming a generic value.
- Total striped line area
- 546.67 ft²
They open the calculator with your figures already in it
Roadway Striping Retroreflective Drop-On Bead Calculator: 20.15 lb — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
What this calculation does not cover
- Calculates the beads that land on the line, not the beads that leave the truck. Drop-on beads bounce, scatter and blow off the edges of the stripe — on an open road in any wind a meaningful share of what the gun throws never embeds — so the ordered quantity needs an allowance above this figure or the crew runs the last stretch bare.
- Mass does not buy retroreflectivity past a point. What matters is embedment depth: the bead has to sink roughly halfway into a wet film and stay there, which is set by the paint's wet film thickness and by how closely the bead gun follows the paint gun down the road. Beads dropped on a film that has already skinned sit on top and sweep off within weeks, at any application rate.
- Models longitudinal striping only. Legends, arrows, crosswalk bars, stop bars and symbol markings are taken off by their own painted area rather than by length times width, and they commonly carry a different bead rate in the specification than a running line does.
The order of work, and the two windows that close
Sequence saves more money here than any unit rate. Sign foundations go in before any surfacing or reinstatement in the verge, because coring a fresh surface for fourteen shafts is a day of work and a set of patches that will always look like patches. The humps follow, onto a footprint that has been swept and dried and bond-coated — Asphalt Institute MS-22, Construction of Quality Asphalt Pavements, is the reference for that bond, and the failure it prevents is a feather edge that lifts on the first hot day. Markings come last, over asphalt that has cooled and given up its surface oils, and the beads come last of all, seconds behind the paint.
Two windows govern the end of the job and neither is negotiable by argument. The first is the paint's own: a minimum surface temperature and a dew point margin, both printed on the product data sheet, outside which the film will not cure into anything that holds beads. The second is measured in seconds — the time the film stays open enough for glass to embed rather than sit on the surface. Losing the first costs a day. Losing the second costs the whole marking package, because a line with beads sitting loose on top of it looks correct in daylight and has to be redone entirely once somebody drives the road after dark.
- Set out and drill every sign shaft while the verge is still open, and pour them in one visit if the concrete route is bags.
- Sweep, dry and bond-coat each hump footprint immediately before laying, not the day before.
- Lay, template and compact the humps, and let them cool fully before anything is painted on them.
- Check surface temperature and dew point against the paint data sheet on the morning of marking, and be prepared to stand the crew down.
- Run paint and beads together on the same pass, with the bead drop close enough behind the gun that the film is still open.
- Take a retroreflectometer reading on the finished lines the same day and record it against the chainages.
Year two, when somebody rings about the paint
The crest markings go first, and they go faster than anything else on the road. A hump concentrates every tyre on the estate onto the same two tracks across the same 600 mm of surface, so the marking wears there while the identical paint on a straight run 30 m away still looks new. It reads as a defect and it is not one; it is the geometry of the thing doing exactly what it was built to do. Say so on the quotation, put an interval against it, and the year-two phone call becomes a maintenance order instead of a dispute.
Retroreflectivity decays in the same quiet way. Beads are lost to abrasion, the paint surface dulls, and grime fills the gaps between the spheres, so the R_L reading falls steadily while the line still looks white in daylight. That is why the reading taken on the day of handover matters: without it there is no baseline, and a complaint about a dark road at night becomes an argument about whether the beads were ever applied. With it, the answer is a second reading and a number.
Everything else is paperwork that costs nothing at the time and is unobtainable later. Keep the mix design and delivery ticket for the hump asphalt, the concrete supply record for the shafts, the bead certificate naming the gradation standard it was supplied against, the panel schedule matched to as-built post positions, and the photographs of each shaft before it was backfilled. A private road gets sold, remortgaged, adopted or resurfaced eventually, and at every one of those moments somebody asks what is actually in the ground. The contractor who can answer that from a folder is in a completely different position from the one reconstructing it from memory.
Three quantities, three suppliers, one alignment
Nothing on this page is bought from the same place as anything else on it. Settle each quantity against its own unit before the alignment is walked, so the small items are not discovered on the day the crew is standing on the road.
- Hump volume, by profile rather than by block — Length across the carriageway × travel-direction dimension × crown height × the shape factor for the actual profile: 0.64 sinusoidal, 0.67 round-top, about 0.8 for a table.
- Hump material, converted to a delivery — A whole estate's worth is a couple of tonnes, which no plant delivers as a load — price the hot boxes or the part-load charge, not just the asphalt.
- Sign shafts, by cylinder and then by hole count — One cubic metre across a whole road sits exactly on the crossover between a part-load charge and a day of bag mixing; decide which before ordering either.
- Marking area, longitudinal and transverse separately — Line runs and hump triangles are different widths and different pass counts; add the areas, do not average the widths.
- Beads, by mass against that area — At the rate the specification names, not at the paint volume — and the answer will round to whole bags, so the risk is storage and moisture rather than quantity.
- The record set, gathered as you go — Mix ticket, concrete supply record, bead gradation certificate, as-built sign positions and a retroreflectometer reading dated the day you finished.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.