No, it is not safe to send your driver's license over email. Don't send it to anyone who makes you feel like you need to send it right away. Scammers often try to trick you by making up fake emergencies. For special circumstances that require a copy, make sure you have verified the legitimacy of the requester and/or company first and then bring a copy in person. If that's not possible, send it through a secure, password-protected email with an expiration date (like Gmail's confidential mode), a Google Drive folder that only allows access from the recipient's email, or through DocSend. This should only be done in rare cases.