Hi
My congested speeds on very high, which I am able to trace back to incorrect unit conversions or the absence of it. I have distance in m, speed in km/h. For the travel time calculations, I am using the script file to convert my distance to km. However, the congested speed calculations are bypassing this distance in km value and still calculating in m.
Probably I am missing some best practices. How may I rectify this ?
Thank you
Ram
Hi Ram,Please refer to our Cubetown demo model and see how the travel times are calculated in assignment. Hopefully, this will give you an idea on best practices.https://communities.bentley.com/products/mobility-simulation-analytics/w/cube-streetlytics-legion-wiki/51411/cubetown-demonstration-model
Thank you.Vipul
I am not sure I understand you. I also have an initial T0 that is based on link distance and link speed, and later in a BPR function. Same as I see in your model. Do I miss something ?
So typically, the T0 is defined in LINKREAD phase as below using link attributes distance and speed where distance and speed are in correct units. In the example below, they are in km and km/hr. Make sure your input distance and speeds are in correct units before using them in assignment. This will ensure correct travel times.
T0=(LI.DISTANCE/LI.SPEED)*60
Thank you. That is what I have, I just convert the meters into Km
Please check this important chapter below in the Voyager Reference Guide:
Home > 6 Highway Program > Phases > LINKREAD phase > Setting TIME, COST, and DIST values
I suggest to clearly state all these variables explicitly at the beginning of the LINKREAD Phase, to make sure of what is used for each variable.
Answer Verified By: Ram B