The Highway Transportation System is made up of people, vehicles, and roadways. square are the least predidable factor.

## Step 1<br />The Highway Transportation System is a complex system that includes people, vehicles, and roadways. Each of these components plays a significant role in the system's overall functionality.<br />## Step 2<br />People are the least predictable factor in this system. This is because human behavior is inherently unpredictable and can vary greatly from person to person.<br />## Step 3<br />People can make mistakes, react differently to the same situation, or even change their behavior based on their mood or other factors. This unpredictability can lead to unexpected events or accidents on the road.