Transportation Geography and Network Science/Topology

Circuits and Trees
Circuits and Trees are two basic structures of planar networks. A circuit is a closed path, with no less than three links, that begins and ends at the same node. A tree is a set of connected lines that cannot form a complete circuit.

At the individual trip level, the treeness is estimated as:

$$ \phi_{tree} = \frac{l_{tb}}{l_{sb}} $$

where:

$$l_{tb}$$ = Length (km) of street segments belonging to a branch network within the buffer,

$$l_{sb}$$ = Total length (km) of the street network within the buffer.