Change FlagEncoder properties at runtime

Is it possible to change the properties of a FlagEncoder (e.g. CarFlagEncoder defaultSpeedMap) at runtime, so after the first initalization of the Graphhopper graph? The goal is to create an object that for example is a car but changes it’s velocity from request to request.

Currently only for DataFlagEncoder and only if you disable CH.

Thanks for your fast response.
Could you give me an example how I could do it properly with a DataFlagEncoder?

Currently we tried to change the properties of exiisting encoders directly in the file by changing the route method. To achive this, we have extended the route method by an configuration object, which contains new property values fpr the encoders.

See the test suite that uses this encoder with the GenericWeighting (e.g. search for weighting=generic).

The GenericWeightingTest class contains the method testDisabledRoadAttributes() where it looks like a new FlagEncoder is added at runtime. The problem here is that also a new and very simple graph is created which might not work for our problem.
The goal is to build a traffic simulation system where each car or pedestrian asks GH for an individual route from a point A to B, but those objects are not uniform, so e.g. not every car behaves the same. There should be slow drivers, fast drivers and others one does first know at runtime. Also a specific car should be able to change its behavior.
So right now our idea is to create a generic CarFlagEncoder and each time a car makes a request it slightly changes the properties of that Encoder. Is that a proper way to do it?