Pre-requisite - road corridors and intersections have been created in your DWG in one of the supported road corridor format's:

Allsite.ai will soon release a feature to automatically build corridors, intersections and cul-de-sacs!

Road Settings (Allsite.ai)

Default road grade data is inherited on project creation. These will be used as default parameters when the road type is changed within your Civil 3D model. By default all road corridors created will inherit the LOCAL road type longitudinal settings, and can be changed on each road region within the corridor.

Editing road settings (i.e. longitudinal grade) per road

After Corridors, intersections, knuckles and cul-de-sac's have been created you can go in and customize longitudinal grade information and other information on the Civil 3D Assembly for each region.

Select the Assembly and edit road settings

Road tangents can be overridden at road-earthworks extent boundary by editing the road alignment feature extended data.

If you want your road to interface with a future stage (and existing ground does not match the levels the future stage will be at) you can 'pull back the earthworks extent' - this gives Level AI room to interface the levels with existing ground.

Remember to add a overland flow path between the road and the earthworks extent if you pull back the earthworks extent - this tells Level AI that the road can drain out via earthworks extent (i.e. be a low point)

Road Settings (Applied to Assembly)

Note - you do not need to configure settings on curb return assemblies. Intersection grade information is defined elsewhere.

Setting	Description
Road Category	This maps to the settings configured for you Allsite.ai project on the web. Changing the type will revert most longitudinal grade parameters to the projects default.
Network Placement	Informs Service AI where services can be applied within the road corridor. This will inherit network placement settings if they are configured in your Allsite.ai project in the web.
Design Speed & Vehicle	This defines the dimensions of the vehicle. This is not used by Level AI and will be used for future layout assist tools.
Min/Max Grade	Defines the bounds that Level AI will vary the design to meet requirements. It is recommended to not over constrain the grade to give Level AI ability to grade.
Max K and Min Sag K, Crest K	Defines longitudinal bounds for the road to be designed with.

Modifier Settings (Applied to Sub Assembly)

Setting	Description
Pit spacing	Informs Service AI of the spacing of catch basin / catch pits along the road.
Network offsets	Informs Service AI where services can be placed relative to the curb.
Crossfall After	If no subassembly is provided defining the grade of road corridor after the current subassembly it uses this field. If none is defined it will default to 2%.

Alignment Settings (Applied to Alignment or simple road centerline)

Setting	Description
Start/End Tangent Elevation Override	Override for the road tangent at connection to earthworks extent. If defined, a Start/End tangent grade is required as well. If not defined uses existing ground elevation at road-earthworks extent boundary.
Start/End Tangent Grade Override	Override for the road tangent grade at connection to earthworks extent. If not defined uses the grade of existing ground at road connection (samples 2 points at road-earthworks extent boundary 2 foot apart)

Sawtooth Control

When Saw-tooth roads are enabled, Level AI can create saw-tooth (seesaw) road profiles — alternating high and low points along a road — to help balance earthworks and create drainage low points. These project settings (under Road Profile Settings and Network Settings) control that behaviour.

Setting	Description
Saw-tooth roads on	Master toggle. Lets Level AI create saw-tooth road profiles where appropriate to balance earthworks. Off by default — the settings below only apply when this is on.
Low points at intersections	Lets Level AI place road low points at intersections when optimising profiles. On by default.
Maximum ponding depth	Maximum allowable ponding depth Level AI checks against for road drainage. Default 0.3 m (≈1 ft).
Minimum highpoint fall depth	Minimum fall required away from road high points during profile optimisation. Default 0.3 m (≈1 ft).
Maximum highpoint to highpoint length	Maximum allowed distance between consecutive road high points. Default 150 m (≈500 ft).
Minimum road start and end K-value cap	Minimum cap on the K-value allowed for road start and end sections during profile optimisation. Default 4.
Set road low points at inlets	Sets road profile low points at inlet (catch pit / catch basin) locations so surface runoff drains toward the inlets. Applies when saw-tooth roads are enabled. Off by default.

For manual, location-specific control over where high and low points occur, draw a Road Profile Control line — this forces a sawtooth high or low point at a chosen crossing on the road centreline.