The Braess’ Paradox
Assume a network with a single O/D pair (1,4) . There are 2 paths available to travelers: p1=(a,c) and p2=(b,d).
For a travel demand of 6, the equilibrium path flows are xp1* = xp2* = 3 and
The equilibrium path travel cost is Cp1= Cp2= 83.
ca(fa)=10 fa cb(fb) = 10fb+50
cc(fc) = fc+50 cd(fd) = 10fd