Speed-Reduction Lines, Rumble Strips and Humps

This page covers the two commands that draw transverse elements meant to slow traffic down: one computes where the lines fall from the deceleration, the other builds the body of the obstacle over a two-point line.

What it does

Speed-reduction lines

The command asks for a point (the obstacle) on an alignment or a curve and spreads transverse bars along it, with a shortening spacing towards the obstacle.

The calculation: from the initial and final speeds comes the deceleration time ta = (v0 − va)/a; divided by the interval t between consecutive lines, it gives the number of intervals n; and the distance of line i is i × (v0·t − 0.5·a·t²·i), with v0 in m/s. The form opens with t = 1.00 s and a = 1.47 m/s², the usual values; both are editable in the side column. The total number of bars is n + 1: there is one bar at the obstacle on top of the n computed.

When you leave the width field at zero, the bar width comes from the initial speed: 0.40 above 80 km/h, 0.30 between 60 and 80, 0.20 below 60.

The other three modes work the same way with a different input: Rumble strip replaces the bars with stripes of constant width and gap along a stretch; Value list uses the distances you type (and loads tabulated ones from the presets combo); Just one places a single bar and asks for the next point, until you press Esc.

Transverse devices (hump and relatives)

The command asks for two points — normally kerb to kerb — and builds the body of the device between them, with the given height, in four families:

• Lombada (hump): the body rectangle plus 45° bands clipped inside it. The rectangle goes on the LOMBADA layer and the bands on the manual yellow horizontal-marking layer.
• Solid: a single filled rectangle.
• Elementos (elements): a staggered grid of circles (or of a chosen block) inside the body, with an optional outline.
• Sonorizador (rumble strip): stripes of constant width and gap crossing the body, repeated along the direction of travel.

The body can be drawn straight into the drawing or inside a block generated on the spot (LOMBADA_H…, CIRCLES_H…, SONORIZADOR_H…), inserted at the middle of the span.

Workflow

Speed-reduction lines

1. Run CAPCAD_MARKING_SPEED_REDUCTION_LINES (or type LRV).
2. Choose the mode (6 to 9) and fill in Initial speed (11) and Final speed (12).
3. Click Select point (1) and click on the alignment, at the obstacle. With Use active alignment (5) ticked CapCad works out on its own which project alignment runs there; without it, you select the curve and then the point.
4. Adjust length (18), width (15), orientation (28, 30, 31) and direction (24, 25). Every Enter redraws.
5. Check the Calc note (27) — it is the calculation record.
6. Click Accept (16) to let go of the reference, or Reset (13) to erase the drawing.

Transverse devices

1. Run CAPCAD_DEVICE_TRANSVERSE (or type LB).
2. Choose the family (53 to 56) and type the body height (62).
3. Click Criar transversalmente com 2 pontos ("create transversely with 2 points", 59) and click the two points, left kerb to right kerb.
4. Choose the reference line (66 to 72): where the line you clicked sits relative to the body.
5. Adjust the family's parameters and press Enter, or click Update (75).
6. To open space in the existing marking, click Trim sinalização horizontal ("trim surface marking", 78).
7. Aceitar ("accept", 74) keeps the body and frees the command for the next one.

The form

The numbers on this page are unique and continuous: 1 to 52 on the LRV form and 53 to 89 on Lombada.

The screenshots below were captured in a Portuguese session; the control numbering is the same in every language. The LRV form has English captions and the tables quote them; the Lombada form is shown in Portuguese in every language, so its captions below are quoted in Portuguese and glossed.

LRV mode, with the side expander (45) open to reveal the n, t and a fields and the explanation of each.

Rumble strip mode: the speeds give way to "Length" (48) and "Gap" (49), the width becomes 0.2, the layer changes to SINA_HOR_BR_SONORIZADOR and the rounding frame disappears.

Value list mode: the presets combo (50), the values box (51) in place of the calc note, and the "Cumulative" box (52) appear.

The Lombada family: "Preset" (63), "Box" (64) and "Vertical" (65).

The Elementos family: the block combo (80), "Angle" (81) and "Scale" (82) appear in the upper frame, and the panel shows "Diâmetro" (83), "Factor X" (84), "FactorY" (85), "Preenchido" (86) and "Box" (87).

The Sonorizador family: "Largura" (88) and "Vão" (89).

The Solid family: no parameter panel — only the height and the reference line.

LRV — selection and mode

LRV — parameters

Transverse devices — family and action

Captions on this form are Portuguese in every language; the gloss follows each one.

Transverse devices — family parameters

Transverse devices — reference line and actions

The "?" beside Como bloco (61) and the label "Bordo esquerdo a direito" ("left kerb to right kerb") above 60 have no number.

How the options combine

The figures below came out of the engines themselves, over a 120 m sample alignment (speed-reduction lines) and over a 6 m span with height 3.7 (transverse devices).

Where the lines fall

v0 = 60 km/h, va = 15 km/h, t = 1.00, a = 1.47: n = 8.503 rounded to 9, and the distances come out 0 — 15.94 — 30.40 — 43.40 — 54.92 — 64.98 — 73.56 — 80.68 — 86.32 — 90.50. Note that the gaps shorten towards the obstacle (on the left).

The same with Multiples of 0.5: 0 — 16 — 30.5 — 43.5 — 55 — 65 — 73.5 — 80.5 — 86.5 — 90.5.

The same calculation with orientation Left: the bars sit entirely on one side of the alignment instead of being centred on it.

The four families of transverse device

Family Lombada, span 6 m, height 3.7: the outer rectangle and the 45° bands clipped inside it. The dashed line is the clicked span, here on the "Centro" reference. The banding under-runs: a triangle at the far corner is left unbanded — see the note below.

Family Solid: a single filled rectangle.

Family Sonorizador, width 0.2 and gap 0.4: the stripes cross the body and repeat along the direction of travel.

Family Elementos, diameter 0.5, Factor X 1 and FactorY 0.5, with "Box": the staggered grid inside the outer rectangle.

Remembered between sessions

Speed-reduction lines: every control on the form is saved on closing and restored on opening, except the calc note, the t, a and n fields, the values box and the presets combo. Whatever mode was saved, the form always reopens on LRV.

Transverse devices: every control is saved and restored.

Notes

• On the LRV form, closing the form does not erase the bars — only the auxiliary cross. Reset erases the bars but keeps the point and the reference, so that Update can rebuild them.
• The 45° bands do not cover the whole hump body. A triangle at the corner opposite the start of the filling is left unbanded. A 6 × 3.7 hump leaves roughly 3.3 m unbanded, and it happens at any aspect ratio. It is visible in the figure above. Add the missing bands by hand.
• If the bars come out mirrored by the offset, flip its sign.
• In Just one mode, every additional point goes through the same calculation as the first, including the extra setback.
• The body of each family is built in a local system running from 0 to the height, and only then rotated and taken to the clicked span; that is why the same reference-line table applies to all four families.
• On AutoCAD the command forces the World UCS during the two clicks and restores yours afterwards.