Iota Index
Measures the ratio between the network and its weighed vertices. It considers the structure, the length and the function of a graph and it is mainly used when data about traffic is not available. It divides the length of a graph (L(G)) by its weight (W(G)). The lower its value, the more efficient the network is. This measure is based on the fact that an intersection (represented as a node) of a high order is able to handle large amounts of traffic. The weight of all nodes in the graph (W(G)) is the summation of each node's order (o) multiplied by 2 for all orders above 1.
These two graphs, A and B, have the same length (80 km) and the same number of nodes (8). However, because of its configuration, graph A is potentially slightly more efficient than graph B.
W(A) = 1+6+6+6+1+1+1+1
W(B) = 1+1+8+1+1+8+1+1