adding weight to roads

Discussion created by gougexueli on Nov 28, 2012
hi all,
I am currently trying to map the pedestrian based on 404 pairs of origins and destinations using network analysis.
I succeeded in creating the routes with only one impedance which is the length of the road.
I have road layer which is categorised into groups, such as "Arterial", "private"," city link". And I know "city link" would not be available for walking. since different types of road may have influence on people's decision about route between origin and destination, I have been thinking to assign different weight to different types.
Q1. what's the systematic way to work out the weight
Q2.I know we can assign the weight to road as a field in the attribute table, but how we can honour the weight as impedance in network analysis?

hope questions are clear.