Song of the Open Road

        US Customs & Border Protection officers can stop a car within one hundred miles of a
            border for the following reasons.

Whether the [body] is close to the border;
whether the [body] is on a known smuggling route;

whether the [body] could have been trying to avoid a checkpoint;
whether the [body] looks unusual in some way;

whether the [body] is of a sort often favored by smugglers;
whether the [body] appears to have been altered or modified;

whether the [body] is being driven in an erratic or unsafe manner;
whether the [body] appears to be traveling in tandem with another [body];

whether the [body] looks as if it has recently been driven off road;
whether the persons in the [body] are paying undue attention to the agent;

whether the persons in the [body] tried to avoid being seen by the agent;
whether the [body] slowed down after seeing the agent.