Within urban areas, vehicles currently drive at maximum speeds, not respecting the local urban speed limits.
This is not broken as of January 10th (#8f8bce1), but is reproducible in the latest version.
I wonder if this change is involved.
https://github.com/jamespetts/simutrans-extended/commit/12b15d3f41a4916211f1401672dd8ea6af711612
Thank you for the report - I have now fixed this. I should be grateful if you could re-test to confirm.