Freeway traffic (vector line)

I posted this question in another forum which has gone unanswered so maybe it should have been posted here.

I would like to add vehicular traffic to some scenery I am creating and I have no idea how to do thsi apart from adding suitable vector lines in scenery.
I have created AI aircraft traffic and also boat traffic but not road traffic.
I have found some documentation by Luis Féliz-Tirado (who developed SBuilderX which allows creation of vector lines for 'freeway traffic' but nothing about the following -
How to allocate a vehicle to use
Are there any 'timetables' to create (so that vehicles will move at certain times)
What 'rate' (% Road Vehicles in FSX setup) needs to be set at to see traffic on these vector lines?

Is there more documentation on this I can read?

Does the 'tag' B work for two way traffic (Luis stated "At initial release of FS X, two-way traffic was not working. Hopefully, the FS X patch will fix this.")



Resource contributor
Hi John,

all you need to place is the vectors themselves, the vehicles are automatically spawned based on the road traffic density slider and the local value for population density. You cannot influence vehicle type.

If you load your CVX .bgl file into TMFViewer and then "PopulationDensity.bgl" (located in \Scenery\BASE\Scenery) on top you can determine whether your area lies in a high-density area or not though that doesn't give you any direct quantitative data. It's possible to generate a local population density file, if needed, with a bit of a work-around via a landclass file set.

The directional tags determine whether the spawned vehicles move away (F) from the first node of a given vector or towards it (T). The B tag doesn't work or rather, it acts the same as either F or T (can't remember which).

To generate opposing traffic on the same road requires parallel vectors tracking the center of each lane. For larger amounts of road traffic one would use a GIS tool to generate those lines. If only a few lines are needed this can be done manually in SBuilderX with a simple trick: assign a width to the vector you've drawn ("4" or "5" works OK for 2-lane roads) then convert that line to a polygon via right-click, then select the resulting polygon and right-click "Make Line" -- et voilà -- a set of perfectly parallel lines.

Be aware that traffic vectors need to have a minimum length of several hundred feet to spawn any traffic.

One additional annoyance with road traffic is that it drops out and gets re-spawned at all QMID15 raster boundaries, meaning every half-mile or so. Moreover, due to that "auto-clipping" by resample.exe, some traffic vectors end up being too short and don't spawn traffic at all, thus you end up with gaps here and there.

Cheers, Holger
Thanks Holger

I suspect that my scenery area has either a very low density or none at all as before I created my scenery there was nothing at all in the area except a airport/single runway a few miles away and a couple of roads. No texture other than conifer trees.

sechelt before.jpg

Thanks for the advice on the B directional tag, vector width and minimum vector lengths etc. Nice tip re getting parallel lines,

I have never created a local population density file.
I have something new to try out and learn.

Thanks again, I now have road traffic on two different roads in my scenery.
Something strange though. The traffic does not appear at the start of my vector line. Where it starts is a long straight section of 'freeway' and before that there are quite a few bends in the road with a short section of road between each bend including the start to the first bend. Maybe that causes the FSX 'engine' to start the vehicles further along the road where it is straight?

I then extended the 'freeway' vector line so that it starts with a longer straight section. Strangely the traffic now starts at the start but when it gets to the part where it used to start the vehicles disappear and then different vehicles appear almost next to where the others disappeared. It's like I had drawn two separate 'freeway' vector lines.
All I can now think of is that I used ADE to create the airport AND to change the altitude of a lot of areas (using triangular polygons with different altitudes at each angle of the triangle) and maybe that is 'upsetting' things. Anyway it is of nuisance value only and I doubt if anyone would notice.

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Resource contributor
There may be a scenery boundary there and all terrain elements (including freeways) are split at that point.
Thanks Tom

Looking at my ADE scenery project there is no scenery boundary at or near that point (I have a large Land Class polygon which extends either way for quite some distance).
What I have either at that point or extremely close are two adjoining Airport Background Flatten polys. They have the same co-ordinates and altitude at the adjoining vertice.
I then selected each poly and 'line' and selected 'HIDE OBJECT' until none were displaying and could not see anything else.

There is nothing in my SBX project anywhere near this point (I used SBX to 'create' some islands in the area).

Anyway it doesn't worry me as it is hardly noticeable when 'flying' at around. It is good to know though what could be causing the 'problem'.