Reported network
coding issues -
Wolfgang Scherr from
PTV America:
1. There seem to be discrepancies between
"speed" and "free flow travel time" in certain links of the
Chicago Regional network. For example, the "Chicago Skyway" (nodes:
8158, 7714, 8184, 8190, 8196, 8246, 8208, ...,2049,
2387) has "speed" of 27MPH while the free flow travel times
correspond to 45MPH. As indicated above, the results reported here rely on free
flow travel times and not on speeds.
2. There are some bi-directional links which in reality represent
mono-directional ramps. The current bi-directional coding creates parallel
alternatives to get on or off the freeway/expressway, which leads to a kind of
local randomness of the link flow solution at these places. I would recommend
coding all ramps as one-ways. Here are a couple of such places, defined by key
node numbers:
A) 6652, 2430, 2429
B) 8559, 8563
C) 2196, 2301
D) 7138, 8994
E) 10265, 10253, 11946