Recently I discovered a way to slow down the road traffic in FSX. It was such a small, minor tweak but it had a big effect of immersion. The default traffic was always too fast, it looked a bit cartoony.  In the past few days I've been spending some time just flying above urban areas and looking at the traffic behaving in more realistic ways.

Unfortunately they seem to be on screen for a limited time. Often I can be admiring the aesthetic effect of the traffic when a a car or truck just instantly disappears. I know it's a compromise the developers made, having traffic stay on the map for your whole flight would be a drain on processor use. But it's still annoying. I have to tell myself that the car pulled into a driveway or something to explain the fact that it disappeared from view.

So is there any obscure computer code way of increasing the time traffic stays on screen? I don't expect them to be continuously onscreen, but every little increase would add to the realism.

There is an old program (no longer available) called Fluisifix that one of the functions was slowing down
road traffic.  I have it.  PM me if you want a copy!