# Road.Engineering: Full AI Guide

Last updated: 2026-10-10

This guide helps an AI assistant explain the current interface at https://road.engineering/.
The app assists engineering judgement. Its results are preliminary engineering aids and
must be checked by a qualified engineer before use. Check inputs, data coverage and site
conditions; an AI assistant does not replace professional review. Full limitations and
licences are at /disclaimers and /sources. This guide describes controls in our own words,
not the engineering requirements for a project.

## Navigation and plans

Signed-out visitors see the landing page. After sign-in, work takes place on one map.
Open main tools from the map toolbar in the Elevation, Sight Distance, Geometric Design or
Analysis groups. Results stay in dockable bottom/side panels. Up to four tools can be open:
choose a tab to focus it; background layers can stay visible, with eye controls where
supported. The focused tool receives clicks and shortcuts. Measurement tools pause open
tools and keep their work; close the measurement or select a main tool to resume.
Esc acts on the current drawing, dialog or tool. Closing work can show an exit confirmation.
Read its options before clearing data.
Not available yet: MGSD, Cross-Section and Volume Analysis are Coming Soon buttons.
They cannot be opened on any plan and have no workflow, so do not describe one. The app
works in metric units (m, km/h); the header units selector is shown as coming soon.
Preset parameter values are editable starting points: check them against the design
standard that governs the project. The app does not certify compliance.
Sight distance parameters use a few presets plus Custom: in SSD, ASD and SISD open the
reaction-time, deceleration or driver-eye-height control (SISD also has observation time),
choose a preset or Custom, enter a value within the bounds shown, then Apply or press Enter.
CSD offers the same menu for driver eye height, and Queue Visibility for eye height,
reaction time and deceleration. SSD and ASD accept reaction time 1 to 4 s and deceleration
0.2 to 0.61; SISD accepts reaction time 1 to 5 s and deceleration 0.1 to 0.8. A value outside
the presets shows as Custom, including values from older saves, which load unchanged.
Defaults are unchanged and exports report the values used.

The header project menu offers Recent, search, View all projects and New project. On phones
it opens from the folder button. The full list includes owned and shared projects.
The sidebar Project Layers panel manages files and imported surfaces/drawings; it does not
select projects. Account settings open from the header user menu.

Free accounts can explore map/crash layers, elevation coverage and basic measurements and
own up to two projects. All available main toolbar tools currently require Professional
access, including Point Elevation and Elevation Profile. Professional is AUD $299 per month,
GST inclusive, with unlimited projects, uploads, DEM elevation and editor
sharing. New accounts currently start with a 7-day Professional trial, no card needed.
The signup trial returns to Free automatically unless you subscribe. Checkout offers a 7-day free trial with a card if you have not used it before.
Founding customer price. Subscribe by 30 June 2027 and your price is held for your first 12 months, even if our list price rises. After that, any price change comes with at least 30 days notice.
Enterprise pricing and team needs
are arranged through sales. Read the current Subscription tab for your account's access.
There is no monthly elevation-point allowance; fair use applies under /terms.

What’s new in the header lists recent product changes. Show me reveals and highlights the related control (for Projects changes, the project button in the header), and you select it to open the tool or area;
highlight dots mark some recent changes. The phone sidebar menu can show a dot for an update
inside it. Read /changelog for the public history.

Public pages include /ai, /changelog, /support, /sources, /disclaimers, /terms, /privacy and
/refunds. Sharing invitations use `/join/<token>`. Tool workflows are in the map app, not
separate tool URLs.

## Tools

### Point Elevation
Open Point Elevation in Elevation. Click to add points; drag a marker to move it. Each point
loads elevation automatically and shows an elevation label and source details. The panel's
table includes coordinates, elevation, source, resolution and survey year. Click a row to
locate its point; remove individual rows or Clear the set. Use + Add when placement is
paused. Export offers CSV and JSON with data and credits.

### Elevation Profile
Open Elevation Profile in Elevation. Place at least two path points, then finish with
Enter, a double-click or the Finish control. Terrain loads automatically. Add Points
extends the path; Refresh samples it again and Clear Profile removes it, also stopping a
refresh that is still running.
Toolbar menus and parameter editors stay open, preserving unfinished input and tab focus
as the panel updates.

Sample spacing chooses Auto or a coarser spacing. The panel reports effective spacing,
source and point count. Vertical exaggeration changes chart display. Chart and Table show
the profile and samples; a sample row locates its point on the map. Chart markups include
elevation difference, slope, distance, three-point radius and sight distance. Parameters
opens the sight-distance fields inside the panel. The sight-distance readout reports
achieved and required distances per direction; when the chord check is enabled, the
readout and drawn sight line use that check and show when it is pending. Strings and Snap
controls support crossings of imported CAD data. Export offers PDF, PNG, CSV and JSON.

### Contours
Open Contours in Elevation. Draw a polygon and finish with Enter or a double-click.
Contours generate within the boundary. Refresh repeats generation with current settings;
Clear removes the result and starts another boundary.
Toolbar menus and parameter editors stay open, preserving unfinished input and tab focus
as the panel updates.

Choose minor/major contour intervals, smoothing and labels. Flow controls adjust drainage
network smoothing, density and opacity. Slope shading offers Batter or Pavement bands with
a legend and opacity. The 3D View tab displays the terrain, starting each new model at a
vertical exaggeration suited to its relief; the slider changes it. Export offers PDF and PNG;
exports include the drawn figures, legends and credits. Interpret drainage as a terrain
estimate, not a surveyed drainage system.
Areas where the only survey is a surface model (roofs and tree canopy, not ground) are
left out of the contours rather than contoured.

### SISD
Open SISD in Sight Distance for Safe Intersection Sight Distance. Follow the panel stages:
place a conflict point, set parameters, then place the minor-road vehicle, braking point and
major-road vehicle as prompted. A user-entered required distance skips the braking-point stage.
The result compares required and actual sight distance with a terrain chart and sight line.
Vehicle selects a car/truck preset; Speed and applicable parameter chips are editable.
Advanced parameters include reaction/observation time, deceleration and eye/object heights.
The panel supplies advisory notes and a disclaimer control. Analysis runs when inputs are
ready. Save/Load stores named analyses in a project. Export offers PDF, PNG, CSV and JSON.
The PDF includes a Street View link for each direction, with Google's imagery credit beside
it where Google has its own imagery nearby.

### ASD
Open ASD in Sight Distance for Approach Sight Distance. Place the intersection target,
set parameters, place the braking point and then the vehicle as prompted. The braking point
supports grade calculation. Review required/actual distances and the terrain sight line.
Choose Vehicle and Speed; applicable grade controls offer Auto or Manual. The advanced area
lets you edit reaction time, deceleration and driver eye height. The target is the road
surface, with fixed object height. Analysis updates from
inputs. Save/Load is available with a project; export offers PDF, PNG, CSV and JSON. The PDF
includes a Street View link from the driver position toward the intersection, with Google's
imagery credit beside it where Google has its own imagery nearby.

### Device
The Device button in Sight Distance opens Device Visibility. It answers one question: can an
approaching driver see this traffic control device from far enough back? Choose the device
in the DEVICE chip. The choices are a roadworks sign on a stand, a sign on a post, a variable
message sign, an arrow board, a portable traffic signal, a traffic controller, a signal head
and other device. A choice gives an editable starting face height and required distance
where it has them: other device needs a face height from you, and values you have already
edited are kept when you change the device. Click the map where the device stands. The speed limit is looked up there, a dashed
circle labelled as the required sight distance is drawn around the device, and the map zooms
out if needed to show all of it. Then click back along the road the driver comes from, on or
beyond the circle. While you place that point the prompt at the cursor gives the distance
from the device and says when it is inside the required distance. The panel opens once both
points are placed, and the check runs.

The required distance starts from the device and the approach speed. The speed is the limit
detected at the approach start, an estimate from the road type (marked EST, to be checked),
or one you enter. Where no limit is found at the approach start but one was found at the
device, the panel offers that speed as a one-click choice and never takes it by itself. With
no usable speed the check waits for one. The REQUIRED chip takes your own distance instead,
and the TIME chip states the requirement as seconds of travel at the design speed; those
seconds are your own requirement. A signal head and other device have no starting distance,
so they use seconds or a distance you enter. A portable traffic signal and a traffic
controller add a note when the approach speed is above 60 km/h. The FACE chip sets the height
of the device face above the ground and the EYE chip the driver eye height for a car or a
truck. The chip that still needs a value is outlined.

Driver positions follow the road between the two points, one every metre. Each sight line
runs straight from the driver's eye to the device face and is tested against the ground it
crosses and against objects placed on the map that are marked as blocking sight, so on a bend
ground on the inside of the curve can block it. The device keeps the position you placed,
including beside the road. Choose Straight line in the APPROACH chip where there is no mapped
road; the result and exports say so. If no road route is found the panel says so in plain
words and offers the straight line and Run the check again.

The result states how far back drivers have an unbroken view of the device, the required
distance, and what limits it. A blocking object is named. For blocking ground it says how far
back it is and whether it is on or off the road line. It reads as Meets the required distance, Marginal, Short by a
number of metres, Not visible on this approach, Approach shorter than the required distance,
or Not fully assessed. It gives no pass or fail verdict. Marginal means the distance is
reached only with the elevation allowance. A distance stated as "at least" is a lower bound:
every sight line assessed was clear. Where the approach placed is shorter than the required
distance, move the approach start further back. A short result suggests the next step, such
as moving the device or adding another sign further back. Where the terrain cannot be used
the result is Not fully assessed, never a pass, and suggests another elevation source or
other points. If the ground level at a placed point cannot be read, the panel says which
point and offers Try again; the check then runs by itself. If an elevation request fails
during the check, the panel shows the reason instead of a result and offers Run the check
again. If placed objects change after a run, the result says it is out of date.

On the map the road the device is visible from is coloured for the result, with the blocking
point marked and the dashed circle at the required distance. Drag either marker to move it;
the check runs again, as it does after an input change. Chart shows the road profile with the
device face at its height and the sight line from the furthest position of the reported
unbroken view. Table lists driver positions every 10 m plus the positions that mark the
reported limit. Pointing at the chart, the map line
or a table row marks the same driver position on the others. A Street View link opens the
limiting position in another tab.

The 3D tab draws the same result on terrain: a sight line for each listed driver position in
its result colour, the device at its face height, the blocking point of the limiting
position, and any placed objects. Drag the ring on the device or the approach start in 3D and the check runs again.
Section, Objects and Labels work as in the other sight distance tools (see 3D view of a
result); the section here is the ground under the straight sight line, where the Chart tab
shows the ground along the road.

Vegetation, barriers, plant, queued vehicles and other signs are tested only where you place
them as objects, and legibility, lighting and night visibility are not assessed. Confirm with
a drive-through. Save/Load is available with a project. Export offers PDF and CSV; the PDF
includes the result, inputs, map, Street View links, profile, driver positions and credits,
and a required capture failure stops the PDF. Snapshot in the 3D view saves that view as a
PNG.

### Queue
The Queue button in Sight Distance opens Queue Visibility. Click the stop point at the
controller, signals or stop line, then a far point back along the road to cover the queue
range you want to check. Confirm the approach speed (detected, estimated or entered) and
check the lane offset, which defaults to 0 m and follows the road line. Set an offset where
needed; positive offsets are left of travel toward the stop point, negative offsets right.
Drag either point or change inputs to update the result automatically.

The Speed control beside the queue type sets the speed along the approach. Posted zones (the
default) reads the mapped posted speed zones along the routed approach. Operating speed
estimates the speed drivers travel from the road geometry and uses posted zones wherever the
model gives no speed. One speed uses the entered speed everywhere; typing a speed switches to
it. The required distance for each queue end uses the highest speed found within that
distance behind it, so a queue end just inside a slower zone still allows for drivers
arriving from the faster one. The approach chart shows a speed row under the availability
bands: solid for posted zones (mapped speed limits), amber dashes for modelled operating
speed, and dashes where no mapped limit is known and the single speed is used. A limit that
is only inferred from the road class is treated as not known. The results column, the chart
and the exports state the speed mode in use; the position readout says which speed a queue
end used and why, and the table, the PDF and the CSV list the speed used at each position.
Where the modelled operating speed is below the posted limit, the tool says so, because that
lowers the required distance. When speed zones cannot be read, the tool says so and uses the
single speed. Check mapped and modelled speeds against the signs on site.

The longest-queue grid has Car and Truck rows and two named checks. A is the roadworks
check, for temporary traffic control: it uses an editable queue sight distance filled from
the approach speed, or your own distance. B is the general check, for any queue, for example
one back from traffic signals: it uses each vehicle's grade-adjusted stopping sight distance
from its speed, reaction time and deceleration. The grid headings, the information control
beside "Longest queue", the table headings and the PDF and CSV carry the same names. Edit
eye heights, back-of-queue height and lane offset in the chips. ADV opens truck speed,
reaction times and deceleration. Select a grid cell to show its limiting position on the
map. Chart and Table show available sight distance by back-of-queue position;
Show details adds grades, terrain blocks, lane offset and longest-queue limits. Available distance
stated as "at least" is a lower bound.

The Queue type control at the start of the input strip switches between Roadworks (the
default, as described above) and Signalised intersection. One click switches and the result
updates. Signalised intersection shows the general check only: the roadworks check, its
distance chip, its grid column and its export columns are left out, because that distance
is a temporary traffic control rule. The detected speed is then the posted speed. It fills
the approach design speed (posted plus 10 km/h; edit it in the Design V chip) and the Urban
or Rural choice (70 km/h or less is urban; one click changes it), which sets the reaction
time to 1.5 s urban or 2.0 s rural (editable in ADV). Compare the longest queue reported
with your own expected 95th percentile back of queue; the tool predicts no queue length.
The information control, the PDF and the CSV state the queue type and the values used.

It reports the longest queue with available sight distance and what limits that result:
terrain obstruction, the elevation allowance, incomplete coverage or the end of the selected
queue range. It gives no pass or fail verdict. A limit relying on the elevation allowance
does not establish the required distance with the strict sight line.
Move the far point to assess longer queues. Check that the dashed road extension behind it
follows your approach. Positions beyond coverage remain unassessed. Back-of-queue positions
are sampled every 5 m and refined to 1 m where sight-distance availability changes, so a small blind stretch can
be missed. Terrain does not model vegetation, barriers, plant or parked vehicles. This does
not predict queue length or replace live queue monitoring. Read the information controls
and disclaimer for the other limits.

On the map, the road within the selected cell's queue range is coloured along each stretch for
that check, using the poorer of the stretch's two ends: green where the required distance is
available, amber where it relies on the elevation allowance, red where the sight line ends
before it and grey where measurement coverage is missing. The profile legend explains the
same colours. Faded colours mean the result is out of date. The tool has no traffic or
queue-estimate inputs. Street View links beside the results open the limiting positions in
another browser tab.

Export offers PDF and CSV for current results. CSV contains the per-position table; PDF
includes longest-queue readouts, limits, map, chart, tables and credits. Required capture
failures stop the PDF. There is no project Save/Load action today.

On the approach profile, Cut/Fill lets you test rebuilt ground: click two profile points to
rebuild the span between them, drag its diamond handles to adjust it, use its cross to remove
it, or choose Clear all. Amber marks cut and violet marks fill. The real terrain is never
changed, and removing the spans restores the original result. The check reruns on the rebuilt
ground, including sight lines across curves. Results, the position table and the PDF and CSV
mark that ground as assumed and list the span distances back from the stop. Hover or select a
queue position to draw sight lines for the enabled Car A, Car B, Truck A and Truck B cases:
a dashed required line from the required driver position, and a solid available line whose
length is the reported available distance, with any obstruction marked separately. Lines are
omitted where the ground or driver position is unavailable.

### SSD
Open SSD in Sight Distance for Stopping Sight Distance. Place the object/hazard, set
parameters, then place the braking point and vehicle. Choose Vehicle and Speed, check grade
(Auto/Manual), and edit reaction time, deceleration and eye/object heights in the advanced
area. Review required/actual distance and the ground/sight-line chart. The required distance
is the calculated value shown to 0.1 m, with no rounding to a 5 m step on a grade. Every sight
distance check (SSD, ASD, SISD, CSD, Queue, Route Analysis and the Elevation Profile readout)
shows required and available distance to 0.1 m and compares those two numbers, so the result
can be reproduced from what is shown. Analysis
runs from the placed points and inputs. Save/Load is available; export offers PDF, PNG, CSV
and JSON. The PDF includes a Street View link from the driver position toward the object,
with Google's imagery credit beside it where Google has its own imagery nearby.
Select Show working beside the result to see how it was reached: the inputs with units, the
calculation with the numbers substituted, the available distance against the required one
(and a required distance you entered yourself, when you set one), the outcome with its
reason, and the source of each value. A source is either a document to check the value
against (title, edition and clause), our own editable default, or a value set for the
analysis. Before an analysis has run, or when one could not finish, it says why. Copy puts
the working on the clipboard, Escape closes it, and the PDF report repeats it as a Working
appendix. It explains the result; it does not certify it.

### MGSD (Coming Soon)

### CSD
Open CSD in Sight Distance for Crossing Sight Distance. Follow the Contact, Start kerb,
Pedestrian, End kerb and Vehicle stages. Set speed, crossing
speed and start-up time and review the heights and crossing width/time. Parameters open as
compact fields in the panel; the menus offer adult and slower-pedestrian values, and for a
child or a cyclist you type your own. Opposite approach (shortcut O) adds another vehicle approach;
each has its own result, chart and sight line. Save/Load stores the analysis in the project.
Export PDF, PNG, CSV or JSON; exports are separated by approach when both are present.

### Route Analysis
Open Route Analysis in Geometric Design. Place a start and end waypoint; the road route
and elevation load. Use the route controls to adjust waypoints. The tabs are Horizontal,
Vertical, Op Speed, SSD, Slope/X-Section, Results and 3D.

Horizontal shows curves/straights and alignment statistics. Edit Alignment exposes control
points and Undo/Redo. Its Export to CAD dialog offers DXF, LandXML or both for the alignment.
Both files state two radii for every curve, the one written to the file and the one the checks
use; curves where they differ by more than 5 percent are flagged in the file, listed at its
top and counted in the dialog before export.
Vertical shows terrain and the posted-speed overlay; use the speed pills and boundary
handles to edit zones. Op Speed shows the modelled operating-speed profile and direction
controls. SSD has editable sight-distance parameters and an All/Deficient filter; select
results to inspect the sight line. Results combines the profile and available analysis
series. Read each tab's export menu for PDF, CSV or chart-copy actions.

In Slope/X-Section, set corridor half-width and station interval, choose Batter analysis or
Pavement analysis and a display unit, then Analyze. The map heatmap and station table link
to cross-section charts. Where part of the corridor has no slope data, the panel and the
map legend say why (for example no survey has ground data there, or a survey could not be
read and re-analysing may recover it). Step stations with arrow keys, click the heatmap for the nearest
section, or use Add section/Alt-click for an extra section. Measure between chart points to
inspect height/slope. Stations CSV, Export to CAD (DXF/LandXML/both) and PDF report are
available. LandXML asks for a coordinate system and carries the alignment with stationed
sections and the same two curve radii and flags as the alignment export; an incompatible section placement stops export with an explanation. If a station
returned no elevation along its section, the PDF and DXF name that chainage, and the PDF
header shows how many of the requested sections were drawn; when none can be drawn the PDF
says so. Sections are restored with the saved route. Slope values describe ground screening, not design approval.

The 3D tab opens a 3D view of the route once its elevation profile has loaded. It shows
a band of terrain along the road (with imagery where available), the alignment as a ribbon, and each
SSD sight line from the driver's eye to the object, in the same colours as the map: green
meets the required distance, amber is marginal, rose is below it. A line that runs into the
ground shows where the terrain blocks it. Click a line, or use the Left/Right arrow keys
(Shift for bigger steps), to select a station: a car or truck sits at the driver position
and a car or road object at the target, sized to the eye and object heights in the SSD
parameters, and the readout gives the station's speed, required and available distance.
Stations that were not assessed appear as grey dots and are reported as not assessed, never
as a pass. Drive (or Space) plays a drive along the route, with the sight line of the
nearest analysed station shown as you go; pause, scrub the slider, or change playback speed
with [ and ]. Choose the speed the vehicle drives at in the playback bar: Operating speed
(the default, which needs an Op Speed result), Posted, Posted plus 10 km/h, or a speed you
type (5 to 150 km/h). The choice is remembered for the signed-in user and the readout names
the speed being driven. Where a posted limit is inferred from the road class the readout
says so; where none is recorded at a point the last zone's limit is carried forward; where
no posted limits are loaded the Limit parameter stands in, as it does for the operating
speed calculation. If the chosen speed has no value the drive does not move and says why.
The drive speed is for display only and changes no result. A drive shows a vehicle
from a chase camera behind and above it: choose any vehicle of the Swept Path library, from
the passenger car to the road trains (V steps through them), or press C for the driver's
eye, where no vehicle body is drawn. The vehicle's front axle follows the route line in the
lane analysed and every unit behind it is placed by the Swept Path tool's own solver, so a
trailer cuts in on a curve by the same amount that tool computes. E shows the ground the
vehicle sweeps as a band along the line. That solver is a low-speed turning model: the
view states the speed it covers (30 km/h for the library vehicles) and shows a notice
whenever the drive is faster, because a real vehicle then tracks differently. The drive
shows tracking only; it does not check steering lock, clearances or lane fit, and the two
road trains have provisional dimensions. Use Swept Path for a turn check. Other
keys: R resets the view, F is fullscreen, L toggles sight lines, S toggles imagery, W steps
the width of the terrain, D starts
or leaves the drive, and Escape leaves the drive, then fullscreen, then the 3D view. Long
routes are shown one stretch of up to 6 km at a time, and the view says which stretch.
The 3D view can sit in three places, chosen with the placement buttons in the view (or P to
step through them) and remembered for the signed-in user: in its tab; in a panel left or
right of the map, resized by dragging the divider; or swapped with the map, where the map
becomes a small inset that still takes clicks and has a button to swap back. On a phone the
side panel is one full-width panel above the map. Beside the map or swapped, the view stays
open while other tabs (the chart, the alignment table) are used, and it keeps its camera,
station and any drive when it moves. The map and the 3D view follow each other: the station
in focus in 3D is marked on the map, and a click on the map beside the route selects that
station in 3D (or moves a drive there). The view takes Escape only while the keyboard is in
it (click it first), wherever it sits, and leaves Escape to an alignment edit in progress.
Away from its tab, after an alignment edit, it offers an Update 3D view button instead of
rebuilding the profile by itself. Behind another tab the view is kept but paused: it draws,
fetches and plays nothing until it is on show again.
Terrain in the 3D view is a band along the road: 300 m wide unless you choose 100 m or
600 m with the Terrain width button (or W), a choice remembered for the signed-in user.
Detail is finest at the road: cells of about 3 m across the road by 6 m along it within
30 m of the centreline, and about 8 m by 16 m beyond. The terrain badge states the spacing
reached, which is a little coarser on a full 6 km stretch at the wider settings. Within
about 4.5 m of the centreline the drawn ground takes the route's elevation profile, so the
ribbon and the driven vehicle sit on the ground in cuttings and on embankments. Where the
terrain source is coarse, its detail is not reported, or it has no data, the view says so
(ground with no data is left blank) and the ground at the road still follows the profile.
Where an SSD result recorded the ground that blocks a sight line, that ground is drawn in.
Section (T) cuts along the sight line of the station in focus and opens it as a chart of the
recorded ground under the line, the sight line, the eye and target, the tops of placed
objects and the blocking point, equal to the sight line chart of that station. Objects (O)
compares the SSD result with and without placed objects: the view without them is marked
What-if, shows the saved result beside it and never replaces it; it covers up to 300
stations that objects could affect and otherwise says it is not available. Labels (B) show
chainage markers (real chainage on a Queensland state road), a dashed ring of the required
distance around the driver, and a sign where each posted speed zone begins in the direction
of travel, dashed where the limit is inferred. More markers appear as you zoom in.
The drawn ground is for display only: it feeds no result, the SSD results it draws are the
ones computed on the SSD tab, and neither replaces a design check.

The 3D view has a set of viewer tools beside its own buttons. Camera (keys 1 to 6) moves
smoothly between the driver's eye and the target's eye of the selected station, a view along
its sight line, a side view, a top-down view and the free orbit you had. Pointing at a sight
line shows its station, required and available distance, result, the minimum clearance the
analysis recorded and what blocks it (the terrain or a named placed object); a click keeps
the readout open and selects the station. These values are the SSD result itself, and a
value the result does not record is shown as not recorded. Measure (M) gives the 3D and
horizontal distance and the height difference between two points, each point's height above
the ground, and the least clearance of the line between them over the ground and from the
nearest placed object; points snap to the ground and to sight lines, and one button measures
the selected sight line. Measurements are read from the terrain and objects as the view
draws them and are a guide, separate from the analysis results. View sets the vertical
exaggeration from 1 to 3 times (X), imagery on or off (S) and a terrain grid or contours
(G); measured values and results stay in true metres whatever the exaggeration. View also
has Sight lines through ground (on by default): where the ground or a placed object is in
front of a sight line, the line stays faintly visible in its own colour. While the ground
loads, the view says so in its middle with how far it has got (the road and sight lines are
drawn at once), then with a slim line along its top edge while more ground or imagery
arrives; if the terrain cannot be loaded it says Terrain unavailable and offers Retry. Snapshot
(Shift+S) saves the view as a PNG with the credits of the imagery in it and a note of any
exaggeration; it is not saved while Google imagery is on show.

On a short map (for example a laptop with the panel open) Route Analysis keeps the slope
legend on screen by folding its on-map controls behind one Map controls button in the
bottom-left corner; the legend lays its bands out in two columns if it still needs the room.
Open Map controls for Layers, Edit alignment and Add cross-section; opening it does not move
the legend. On a very small map (a phone held sideways, or a map only a few hundred pixels
tall) the legend can still run off the top edge, and below about 165 px of map it is hidden because nothing would be readable: enlarge the map.

If the terrain elevation fetch fails, a notice on every tab that needs it names the failure
and offers Retry terrain. If posted speed limits cannot be loaded (including when the map
data service reports it could not trace the route), a notice says so and the app retries
three times by itself, then leaves a Retry button; the Limit parameter applies while no
posted zones are available. Zones whose limit is inferred from the road class, not read from
a tagged limit, are flagged, and the speeds should be checked against signage. Editing a
posted speed zone while operating speed is calculating cancels that run, so results computed
before the edit are never shown as up to date.

Where the elevation source returns no value for part of the route, the Vertical and Results
charts hatch that stretch, a notice gives the number of stretches and their total length, and
the minimum, maximum, gain and average grade are taken only over stations that have a value;
Points reads as stations with a value out of stations sampled. Terrain-based results are not
assessed over such a stretch, the vertical CSV leaves those rows empty and labelled, and the
CAD draped centreline is not drawn across it. Superelevation (crossfall on a curve) is
positive when the lane falls toward the inside of the curve, for both travel directions; a
manual value is entered once and applies both ways. When crossfall is missing, the model
assumes 3 percent adverse crossfall (the lane falling away from the curve), which lowers the
limiting curve speed and raises side friction on that curve, and shows the value as assumed.
A speed above the limiting curve speed on such a curve says it rests on the assumed crossfall
and asks for the crossfall to be measured or entered. A measured or typed crossfall is used
as given, but speeds and checks on that curve can still depend on a neighbouring assumed
curve, because speed carries from one curve to the next. Analyses saved before this rule keep
their A to B results and reopen without B to A operating-speed or sight-distance results;
one saved with manual crossfall values lists them for re-entry and reopens without results
in either direction. A kept A to B result that a short-straight speed correction changes
is marked for refresh. Re-run what is missing or marked. In-lane sight distance that cannot run because the
operating-speed result has no known bank side says so beside the inputs.

The road-data line can show Queensland road authority chainage and AADT, with Re-query.
Lookups can be unavailable when the route cannot be matched to a suitable road section,
when its road names disagree with the declared road, or when the recorded chainage on
that stretch does not advance at the distance travelled. The RA CH switch on the
Horizontal tab adds road authority chainage columns to the table; with no chainage
reference it stays visible, switched off, and its tooltip gives the reason. A chainage
reference saved with a project is checked again when the project opens: it is shown
only once the lookup confirms it, and if the lookup cannot be made the title says the
saved reference was not re-checked.
Where shown, nearby traffic-count badges open published year-by-year count history.
Save stores named routes in the current project; it needs at least two waypoints and valid
geometry. Load reopens saved routes. Read the current panel if data needs to be recalculated.
A saved route that does not record the map zone its alignment was fitted in, and lies outside
eastern Australia, opens with a notice that its lengths, radii and chainages may be overstated
and offers Re-run alignment. A route analysed or re-run now records the zone when it is saved
and reopens without the notice; saving an older route again without a re-run keeps the notice.

### Swept Path
Open Swept Path in Geometric Design. Select a vehicle, Speed/minimum radius, Design or Check
role, Body/Wheel/Both envelope and clearance. Design and Check select the vehicle's role;
both retain clearance. Custom vehicles can be added or edited through the vehicle editor.

Use Add Points and click waypoints. A ghost vehicle previews the next turn; Enter or Stop
finishes placement. Each turn can be Automatic or Set radius, with the radius control
starting at the vehicle minimum. New Automatic turns follow that minimum smoothly as you
move the pointer. An unreachable point offers a reachable alternative before placement.
The bracket keys widen/tighten the next turn within the minimum; Ctrl+Z undoes a waypoint
and right-click removes one. While placing, a chip at the cursor reads the radius the next
turn will take, or why the point cannot be reached. Review simulation warnings as well as the
drawn envelope. The results row states the tightest radius of the drawn path (front axle
centre) beside the vehicle minimum at the selected speed, and the peak steering against the
steering lock; a path tighter than the vehicle minimum is flagged. Ground enclosed by a
looping path is left out of the envelope and its area. A path that stops at a steering or
articulation limit ends there: later points are listed as not solved.
Animation has playback and timeline controls. Export offers PNG, PDF and DXF and prints
vehicle, speed, clearance and turn-radius details along with the required credits.

### Cross-Section (Coming Soon)

### Crash Analytics
Open Crash Analytics in Analysis. Edit filters opens the sidebar editor for region,
severity, years, collision type and supported geographic areas. Regions are QLD, NSW, VIC,
ACT, SA, TAS and NZ. Years and recorded fields vary by region; absence is not a zero count.
Severity is labelled Fatal, Serious injury, Moderate injury, Minor injury and Property damage only
in every region; this is a common display scale. Hover, focus or tap a label to see the term the
source uses, and the record export carries it in its own "Source term(s) for this severity group" column.
Filter options show progress while loading. Retry reloads current options, including
options added by a data update. If a region cannot be reached, existing selections stay
in place and any previously saved options are shown as incomplete.
If the full set of crashes for a drawn area cannot load, a notice on the map says so and
offers Retry; the map then shows only the crashes loaded for the current view.
While Crash Analytics is the focused tool, press P to draw a polygon or C for a circle;
finish the polygon with Enter/double-click.
Esc cancels drawing. The area chip clears drawn areas; comparison and coverage notes help
interpret the selection.

Tabs are Overview, Spatial, Time, Trend, Crash %, Custom and Details. Spatial charts group
crashes by surface condition, alignment and severity/speed limit; heatmap and clusters are
map layers. Details is a record table. Record exports include recorded fields and mark
fields a region does not record. Export controls are available across the tabs; records
can be exported to CSV/Excel, and a landscape PDF report includes map, charts and listings.
Chart-copy actions put an image on the clipboard; they are not file downloads.
The Custom analysis tab's Export menu also saves its table as CSV and its chart as a PNG file.

### Volume Analysis (Coming Soon)

### Aquaplaning
Open Aquaplaning in Analysis. Click a pavement point to fetch nearby terrain and trace a
flow path; each check gets a numbered pin. Select a pin or list entry to revisit it.
Hover over the drawn path to preview a snapped end, then click once to set that path end.
Click elsewhere to start another check; Resume re-enables placement when paused.

Set site context, rainfall intensity and surface texture (preset or custom). The water
film depth limits (desirable, an optional accepted limit, and absolute) are prefilled under
the other inputs and can be changed; your limits are remembered in your browser, each check
keeps the limits it was judged against, results and exports say when they differ from the
defaults, Use defaults restores them, and cleared limits give no verdict. The aged/worn
check explores another texture value. Smoothing and slope/contour/flow overlays help inspect
the fetched terrain. Results show water film depth along the traced path, status, metrics
and a limit readout. Out-of-range inputs are marked extrapolated. Missing terrain leaves
no verdict unless the measured part already exceeds the absolute limit. Water arriving from outside
the traced path is not modelled. Export PDF or CSV includes all checks and source credits,
naming the elevation dataset where the source reports one.

## Interpreting results and exports

The three Coming Soon buttons above cannot be opened on any plan and have no workflow today.
For the available sight-distance tools, check the required and actual values, source and
parameters. Marginal means the sight line needs the 0.1 m elevation-data allowance to clear;
it is not a pass. TIN surfaces use no such allowance. Ground-data gaps can make a sight line
not assessed, unless measured ground already proves an obstruction. A badge does not
certify a design or account for every obstacle at the site.

Use each panel's disclaimer/information control and export menu. Formats differ by tool.
Reports and map/chart figures carry captions and credits for their sources. Keep
credits with a reused figure and read /sources for full licences. Map capture can be refused
when restricted imagery is involved. Follow the message and use an allowed map source.
During a required map/chart capture, keep the browser tab visible; a background export may
wait until you return. Route maps ignore map dragging/zooming during capture. If a required
figure cannot be captured, the export is refused and the panel names the reason; retry after
the map/chart is ready. CSV exports open with their text symbols correctly in Excel.

## Measurements, map layers and data

The separate measurement toolbar offers Distance (D), 3-Point Radius (R), Circle (C),
Grade (G), Polygon Area (P), Point Elevation (E), Posted Speed (S), Property Info (I) and
AADT Check. Grade and spot elevation need paid access. Esc exits measurement. Main-tool
points and panels are preserved while measurement pauses them.

AADT Check is paid and limited to Queensland state-controlled roads. Click a road to read
its latest published annual average daily traffic, road section, chainage and source.
A click counts when it is within 10 m of a carriageway's line; where two carriageways
or a ramp are both that close, each is listed for you to choose.
Nearby count sites open their recorded yearly history. This is published count data,
not a live vehicle count. Posted speed and cadastral lookups depend on their source coverage.

In Map layers, enable Road Chainage (QLD) with paid access. At street scale, state-controlled
roads show cross-road ticks every 100 m and kilometre labels; closer zoom adds tick values.

Elevation data shows coverage/survey information, including provider, product type
(bare-earth or surface model where recorded), resolution and survey year. Read local source
and vertical-datum information before comparing heights. Availability differs across
Australia and New Zealand and within each area. There is no promise of coverage at any
arbitrary location. Routing and posted speed use road-network data; road geometry and
speed limits should be checked on site. Crash records are historical published data with
region-specific completeness. Full provider credits, licences and limits are at /sources.

### 3D view of a result

SSD, ASD, SISD, CSD, Queue, Device, Swept Path and the Elevation Profile sight distance
readout each have a 3D tab. It draws the last result of that tool on a band of terrain along the line and
never works a result out again.

- Sight lines are coloured by result: meets, marginal, below required. A blocked line has a
  dot at the point that blocks it and is faint beyond that point. A line or position that was
  not assessed is grey, and its reason is shown in the result card.
- The driver and the target are drawn at the eye and object heights the chart uses, with any
  objects placed on the map. If the objects have changed since the run, the view says the
  result is out of date.
- SISD shows both directions between the minor and major road drivers and the conflict point.
  CSD shows each approach. Queue shows the queue, the required, available and blocked lines of
  the selected position, the other positions and the limiting position. Device shows a sight
  line from each listed driver position to the device face, and marks the blocking point on
  the limiting one only.
- The view can stay in its tab, sit in a panel left or right of the map, or swap with the map
  (P steps through these). It has the camera views (keys 1 to 6), the sight line readout,
  Measure (M), the view settings and Snapshot (Shift+S) of the Route Analysis 3D view, plus
  Reset (R), sight lines on or off (L) and terrain width (W).
- Drag the ring on the driver or the target in 3D to move that point, or press D to select a
  point, the arrow keys to move it (Shift for 10 m) and Enter to drop it. The tool then runs
  again exactly as it does after dragging its marker on the map. Escape cancels a move.
- Swept Path shows every unit of the vehicle at its simulated position for the current frame,
  so an articulated vehicle bends as simulated, with the swept envelope on the ground. Play
  (Space) and Left and Right step the same frames as the playback bar under the map. Where
  there is no terrain yet, the vehicle is shown on a flat plane and the view says so.
- In the Elevation Profile, turn sight distance analysis on and point at the chart: the 3D
  tab shows that readout. Placed objects are shown there, but that readout does not test them.
- Section (T) cuts along the sight line in focus: the slice is drawn in 3D and opens as a chart
  of the ground, the sight line, the eye and the target, the tops of placed objects the line
  crosses and the blocking point the result records. Point at the chart, or use Left and Right,
  to read the distance, ground, sight line height and clearance. It is drawn as the tool's own
  chart draws that line. In Queue and Device the section is the ground under the straight
  sight line, where the tool's chart shows the ground along the road, and the panel says so.
- Objects (O) compares the result with and without placed objects. The view without them is
  marked What-if, shows the saved result beside it, and never replaces the saved result. It is
  worked out by the same run, on the same ground, at the time of the run; a result restored
  from a save asks you to run the analysis again before comparing. The Elevation Profile
  readout does not test placed objects, so it has nothing to compare.
- Labels (B, in the View menu): chainage or distance markers along the line and a dashed ring
  of the required distance around the driver. More markers appear as you zoom in. The ring is
  a straight-line radius; where the tool measures the distance along the road it says so.

The 3D view is an aid to reading a result. It does not certify one.

### Objects that block sight lines

Objects on the map toolbar (paid) opens a small panel beside the toolbar. Pick a category
(Vehicles, Trees, Signs, Fencing, Barriers, Walls, People, Custom), pick a kind, then click
the map to place it; keep clicking to place more, Esc stops. Click an object to select it: drag the
square handle to move it, drag the round handle to turn it, and edit its name, length,
width, height and direction in the panel. A size outside the allowed range is refused with
the reason and the object keeps its last valid size. Delete removes the selected object;
Undo and Redo (Ctrl+Z, Ctrl+Y) step through changes. The sizes offered are typical starting
values to edit, not design values. While the panel is open, map clicks belong to it and open
tools pause, as with measurements.

Fencing, Barriers and Walls are drawn as a line, not placed as a single object. Pick the
kind (solid, chain link or wire fence; W-beam guardrail with or without rubrail, concrete,
water-filled or wire rope barrier; vegetation line; wall), then click the map along the
line: each click adds a point and the length so far is shown. Double-click, press Enter or
choose Finish to end the line; Backspace takes back the last point and Esc drops the line
being drawn. A finished line is selected: set its height and thickness in the panel, drag a
point to move it, drag the small handle between two points to add one, and click a point to
remove it. A vegetation line marks the edge of vegetation and stands as an upright surface
6 m high until you change it; a wall is any other upright surface, such as a noise wall,
with the name and height you give it. Heights from 0.05 m to 40 m are accepted and a line
can be up to 5 km long with up to 200 points; anything outside is refused with the reason.
Each segment of a line counts as one object toward the 500 a project can hold. A fence or
barrier placed as a single object before this change still loads and shows as it was.

Objects belong to the open project and are saved with it automatically; the panel says
when they are saved, when a viewer cannot change them, or when they last only for the
session (no project open). They show as footprints and lines on the map and as solids
standing on the terrain in the Route Analysis 3D tab and the Contours 3D model. In 3D a
barrier or fence is its model repeated along the line, and a vegetation line or wall is a
plain upright surface; the top follows the ground along the line.

SISD, ASD, SSD, CSD, Queue, Device and Route Analysis sight-line checks treat every object
marked
"Blocks sight lines" as a solid from the ground to its height, on the ground the check
already uses. A line passing through one is blocked and the result and exports name the
object; a line passing over or beside it is unchanged. A drawn line blocks in the same
way along its whole length, bends included, from the ground under it up to its height; a
sight line that passes above its top is not blocked. See-through kinds (wire and chain
link fences, wire rope barrier, a sign on a post) start unmarked; tick the box to count
them. A whole object is solid: there is no see-under for a sign panel or a tree canopy. If
an object cannot be tested (the ground under it is missing, a saved object cannot be read,
or the project's objects have not loaded) the line is not assessed, never clear. A result
calculated before the objects changed shows a notice asking for the check to be run again.
With no objects placed, every result is as before. This is a screening aid, not a
certification that a sight line is clear.

## Imports and projects

Open Project Layers in the sidebar and select Import File. Drop/browse for .12da, .12daz,
.dxf, .kml, .kmz, LandXML (.xml), .zip (shapefile), or .obj and .ply surfaces, up to 1 GB. The dialog inspects the file.
A simple file can import automatically; otherwise choose the detected groups, Surface or
Drawing type and surface label. Each group shows what it holds; a group with no surface
triangles can only be imported as a Drawing. When the import finishes, any group that was
skipped is listed with the reason, and if nothing could be imported the dialog offers Back to
selection. A file refused for a safety reason imports nothing. Confirm or choose the correct coordinate system with the
CRS/zone picker. A project owner can set the project default. Do not guess a projection or
assume geographic coordinates are projected metres.

Imported surfaces appear under Surfaces and drawings under Drawings. Tools can use an
uploaded TIN surface as ground. TIN flow density controls how much of the network is shown.
Flow lines carry on through dips of up to 5 cm; a deeper low spot ends the line and is marked
as a ponding point. Treat a ponding point as a place to check, not a measured pond.
A warning flags a surface whose nulled-area record is unavailable; check the surface before
relying on ground inside those areas.

SISD, ASD, SSD and CSD Save/Load buttons manage named analyses in the selected project.
Save requires tool data; Load opens stored analyses and restores their saved points,
parameters and results. A CSD analysis saved from October 2026 reopens with both approaches
and its result; an older CSD save shows as a saved result and asks for a re-run. With no project selected, open/create one when prompted. Route
Analysis Save needs two waypoints and valid route geometry. Saving is explicit; do not
promise every open tool is saved by creating a project.

Owners manage project sharing and deletion. An invitation to someone who already has an
account appears at the top of their Projects menu with Accept and Decline, showing the project,
who sent it and the address it was sent to; accepting opens the project. Decline can be undone
for a few seconds. Someone without an account gets an email link that opens at `/join/<token>`. Viewers can
read/load; editors can save changes and overwrite analyses; owners can delete saved entries.
Editor-level sharing needs paid access. The interface shows the actions your role permits.

## Accounts, devices and troubleshooting

Sign in with Google, Microsoft or email/password; email magic links and password reset are
also available. Account settings has Profile, Security, Subscription and Preferences.
The active-device limits are Free 1, Professional 2 and Enterprise 3, across device types.
A new device may require an emailed verification code. Follow the verification dialog and
its resend/error controls; do not assume verification is required on every sign-in.
Security lists active sessions and trusted devices. Sign out another device to free a
session slot. Removing a trusted device means it can require verification on next sign-in.
If these lists cannot load, read the error and retry rather than assuming there are none.

- Tool does not open: check paid access in Subscription, or its Coming Soon label.
- No elevation/profile: check local coverage and source, the placed points and completion
  state. Use a suitable uploaded survey surface where supported.
- No sight-distance result: complete the prompted stages, confirm parameters and read the
  error/coverage message. Incomplete ground is not a passing result.
- Queue waits for inputs: confirm a valid approach speed and check the lane offset; check both points
  and the routed/dashed approach. Missing terrain or road extension limits the assessed range.
- Import fails: check format, file size, groups and coordinate system; follow the dialog.
- Save unavailable: select a project, place the required inputs and check your shared role.
- New project limit: Free ownership is limited to two; remove an unused project or upgrade.
- Service unavailable: brief connection interruptions can retain work while a tool retries.
  Follow the Retry/status message. A failed project list does not mean your projects vanished.
- Sign-in/device error: use the dialog's retry, verification, password reset or session
  controls; contact support if it persists. Do not erase local app data as a first step.
- Blank map: check the connection and whether a browser extension blocks requests.
- Unexpected result: review inputs, terrain source, coverage and site conditions with a
  qualified engineer. Do not treat the assistant's explanation as engineering approval.

Support: https://road.engineering/support and support@road.engineering.
Human copy/download page: https://road.engineering/ai.
Data sources: https://road.engineering/sources. Disclaimers: https://road.engineering/disclaimers.
Account terms: /terms, /privacy and /refunds. Product history: /changelog.