Ned is engaging in stereotyping.
Explanation:
Stereotype means exhibiting a generalized belief about a particular category of people. The people engaging is stereotyping have idea about others by just seeing their appearance or outlook. They may go wrong about their decision. The idea of those kinds of people will not be correct all the time.
In the above scenario, Ned was travelling in the car with his friend. He told his friend that the driver would be a lady as the car was driven slowly in the highway. Ned exposed stereotyping, because without knowing the fact about driver he simply claims that it would be a lady driver.