It may be important to many users to send a copy of the delivery note to the transporter - for example to obtain signature of customer at time of delivery. Or to use the Delivery Note as a delivery instruction to the transporter. Currently this can be done by manually sending the delivery note to the transporter. transporter_email is not an option available in email Notification.
I had posted earlier a request for a custom script to send the delivery note autoimatically via Notification. It requires setting up a custom field and a custom script with dynamic filter to accomplish it. Was not easy - as I had to post several times and finally got help from a pro. I would like to request that this feature be standardized and added to server side of ERPNext so that transporter_email is an option for Delivery Note notification.
See below link to post for further details: