You’re going to have to make a convincing argument that alerting people of a traffic cop isn’t the same as alerting people of police presence in general, and that the merits of one has more weight for the usage of someone already committing crimes.
As it is, by batting for the legality of alerting traffic checks, you’re already batting for the alert and notification of police presence - because that’s what traffic checks consist of
Courts are not stupid. You're not "altering people of police presence in general" when you're making or participating an app that is clearly intended to help people facing the legal consequences of their actions.
You still need to generate a convincing argument that "alerting people of police presence in general" has any more weighted use from criminals, to avoid legal consequences, than speeding trap alerts - which we already have settled case law for. You have not done so.
As it is, by batting for the legality of alerting traffic checks, you’re already batting for the alert and notification of police presence - because that’s what traffic checks consist of