Simply write us and tell us you want to cancel. As to trucks not carrying an ad, cancellations are effective on the first day of the subsequent billing cycle following the billing cycle in which you cancel. However, you may not cancel our agreement as to any truck currently carrying any ad until that date which is thirty (30) days before the end of any ad’s campaign (i.e., if one of your ad’s campaigns ends on March 31, another on April 30, and another on May 31 all on the same truck, you may not cancel the agreement as to that truck before April 30).