Authorities say a Canadian man from Tunisia crossed legally into the U.S. days before stabbing a police officer in the neck at a Michigan airport. The attack raises questions about security along the northern border, including what the process is for travelers and how many people are detained or denied entry. A look at some common questions and answers.
Q: HOW MANY PEOPLE CROSS FROM CANADA INTO U.S. EACH DAY?
A: U.S. Customs and Border Protection says about 216,000 people come into the U.S. from Canada on a typical day. That's out of an average of 1.2 million people processed daily at all points of entry into the U.S. According to the Bureau of Transportation...