The car-following and merging models described above capture behavior in response to the leading vehicle or vehicles from competing upstream lanes. In making acceleration decisions, another set of constraints is imposed by various downstream events within driver's view. Such events include: (i) traffic signal and signs; (ii) incidents; (iii) making a connection to the next link at the downstream node; and (iv) yielding to another vehicle switching into the same lane. These events may also influence drivers' lane change decisions, which are discussed in Section "Lane Changing".