Tools/street_mesh.py builds the corridor in the project frame from the measured
profile: carriageway -10.5..+10.5 m, kerbs 0.15 m (0.13 m as built), sidewalks
4.0 m south and 5.3 m north, all elevations sampled from the DEM. Kerbs flush at
the three signalised crossings. Crown at mid-block reproduces the cross-sections
to the centimetre.
