VMT label on html overview page
bettinardi opened this issue · 1 comments
The overview tab of the visualizer html has a value titled "Total VMT". However this number is far less than the total VMT under the assignment tab. Looking back the VMT reported on the overview screen is computed as an approximation from the trip table as:
SUM[(Trip_weight/occupancy) * trip_distance]
The one in assignment tab is computed from the network links as:
SUM[Link volume * link_length]
The overview page only includes residential demand, VMT page has all demand.
Therefore the overview page VMT label should be changed to something like "Total Personal VMT", or "Total Residential VMT". Residential sounds better, but it's a little misleading, because the population will likely include residents and visitors, so maybe "Total Personal VMT", or "Total Personal Transport VMT" - if that table isn't too long.
Following up on this - I think there is a flaw somewhere in the VMT calculations that needs to be cleaned up. If you look at the assignment VMT tab for the base year, it's around 4M. External VMT is around 1.3M. The the overview page has 3.8M. There doesn't seem to be anyway for that math to work out. I believe the overview page is the page with the bug. That calculation should be reviewed and revised.