Other edits affecting turns
Besides editing turns and removing or adding fields to a turn feature class, there are other edits you can make in a network that affect turns. In some cases, these edits may result in having to remove a turn, rebuild the network, or another solution. See the sections below for editing examples.
Changing the topology of a line feature referenced by a turn
If a line feature that participates in a network that supports turns is changed, it impacts the turn that references the particular line feature. For example, if you have a restricted left turn from First Avenue to Orchard Street and you modify the shape of Orchard Street such that it no longer connects to First Avenue, the restricted left turn feature referencing Orchard Street is no longer appropriate.
If the turn feature is no longer appropriate after modifying the line features, delete the turn feature.
If the modifications to the line feature (Orchard Street) are of a nature that does not affect its intersection with First Avenue, the turn feature is considered appropriate. You will then rebuild the network and use editing operations to fix the turn feature.
Learn more about editing and maintaining turn features
If you take no action after modifying the line features, the turn feature may be flagged as an error during the next network build. The error would be that the line features referenced by the turn no longer connect.
Deleting a line feature referenced by a turn
In a geodatabase
If one of the line features referenced by a turn is deleted, the turn feature that references the feature is no longer appropriate. In such a case, you should delete the turn feature.
If any other line features within the source are deleted and the turn feature is still appropriate after modifying the line features, rebuild the network and use the edit operations to fix the turn.
If you take no action after deleting the line features, the turn feature will be flagged as an error during the next network build.
In a shapefile workspace
Shapefiles don't have a persistent unique identifier, unlike the geodatabase’s ObjectID (OID) field. The OID for a shapefile is the record number in the attribute table (stored in a .dbf file), which is always numbered from 0 to N-1. When you delete a feature from the line shapefile, all records in the shapefile after the deleted feature (all features with a higher record number) receive a new record number one less than their current record number. For example, if a feature with record number 57 is deleted, the feature that had record number 58 will now have record number 57; the feature that had record number 59 will now have record number 58, and so on. Because of this shift in record numbers, the features in the turn feature class will now reference the incorrect line features.
Because of this limitation of .dbf files, if you plan to edit the edge feature source in the shapefile network dataset, you must do the following to your data before editing the edge feature source:
- If the edge feature source does not have an alternate ID field, for example, a unique identifier provided by a data vendor, you must create and populate such a field.
- Run the Populate Alternate ID Fields tool for each turn feature class. This tool creates additional fields on the turn feature class that reference the edges by alternate IDs.
After you perform edits to the edge feature source, which includes the deletion of a line feature, then you must do the following:
- Run the Update By Alternate ID Fields tool for each turn feature class. This tool updates the Edge#FID field values on the turn feature class based on the alternate IDs stored on each turn feature.
- Build the network.
Splitting a line feature referenced by a turn
ArcGIS gives you various options for splitting lines, such as the Split tool 
and the Proportion tool 
.
Learn more about the ways to split a line feature
These tools perform the same basic operation on the line feature to be split: deleting the line feature and creating new smaller line features in its place.
If the turn feature is no longer appropriate after the line feature has been split, delete the turn feature.
If the turn feature is still appropriate after the split of the line features, rebuild the network and use the editing operations to fix the turn feature.
Learn more about modifying the edge sequence of a turn feature.
If you take no action after splitting the line features, the turn feature will be flagged as an error during the next network build, since the original referenced feature no longer exists.
Turn feature classes in a shapefile workspace have the same ID shift problem, because splitting line features actually causes a deletion of the feature and the creation of new smaller features in its place. You must use the Populate Alternate ID Fields tool before editing to create alternate ID values and use the Update By Alternate ID Fields tool after performing the edits.
Merging line features referenced by a turn
If the turn feature is no longer appropriate after the line features have been merged, delete the turn feature.
If the turn feature is still appropriate after the merging of the line features, rebuild the network and use the editing operations to fix the turn feature.
Learn more about editing and maintaining turn features
If you take no action after merging the line features, the turn feature will most likely be flagged as an error during the next network build, since all but one of the original referenced features no longer exist.
Since merging line features actually causes the elongation of one of the features and the deletion of all the other features, turn feature classes in a shapefile workspace have an ID shift problem. You must use the Populate Alternate ID Fields tool before editing to create alternate ID values and use the Update By Alternate ID Fields tool after performing the edits.