Assignment Done - Which Modifications Are Still Safe?

In earlier releases of EMME/2, any modification of the input data in an already assigned scenario would lead to the loss of the "assigned" status of the scenario, i.e. the results of the assignment(s) were no longer available for analysis. While this is necessary when the modifications are structural (i.e. concern the information on which the assignment results are based upon), it is questionable when the data modified has no influence on the assignment results, such as e.g. the link types or the node coordinates.

In release 3.0, this aspect has undergone a complete overhaul, so that any existing assignment results are invalidated only if absolutely necessary. The following table summarizes how existing assignment results are affected by the different modifications. Note that this table describes the behavior of release 3.0 and is not applicable to earlier releases.

Module Modification Assignment

Auto Transit

1.23 Titles, units - any modification no no

1.41 Demarcations - any modification no no

2.01 Add, modify or delete a mode no no

2.02 Add, modify or delete a vehicle type no no

2.11 Input base network yes yes

2.12 Add or delete centroid/node/link yes yes

Modify nodes (any attribute) no no

Modify links (length) yes yes

Modify links (transit modes) no yes

Modify links (auto mode, lanes, vdf) yes no

Modify links (type, ul) no no

2.21 Input transit lines no yes

2.22 Initialize transit lines no yes

Add or delete a line no yes

Modify headway, speed no yes

Modify name, veh., descr., user data no no

Modify a line segment (dwt) no yes

Modify a line segment (ttf, layover) no no

Modify an itinerary no yes

2.31 Initialize turn penalty table yes no

Add, modify or delete a turn yes no

2.41 Modify nodes (any attribute) no no

Modify links (length) yes yes

" " (lanes, vdf) yes no

" " (type, ul) no no

2.43 Marking of elements no no

3.01-3.22 Any modification no no

4.11-4.14 Any modification no no

5.11 Auto assignment (more iterations) no no

Auto assignment (new assignment) yes no

Transit assignment (more demand) no no

Transit assignment (new assignment) no yes