If you contest the violation, you will have an opportunity to address the matter in court. Do not argue with the Deputy. Be honest with the Deputy. If you really didn't see the stop sign, or were unaware of the speed limit, let the Deputy know. Being honest about any situation is the best approach.
Many Departments use single-officer patrol cars, especially in the suburbs.
It is normal to see two or three marked patrol cars on a routine traffic stop, especially at night. This is to ensure the Deputy's safety. Finally, if you receive a ticket, please accept it calmly. Signing it is not an admission of guilt, it's only a promise to appear in court at a later time. State law mandates that if you refuse to sign the citation, you will be arrested.