In the Sterling Hills neighborhood this can be an issue with the shared green spaces in back of the properties, where pet owners are tempted to use the space as an open dog run. Other owners may see this and think they don’t have to have their dog on a leash there, either.
If you rent, this may or may not be stated clearly in your lease, but it is a City Ordinance, 6.04.120:
https://www.lincoln.ne.gov/
If you see your neighbor failing to observe this with their dog, please approach them and address it with them 1:1. Calling Animal Control is a last resort.