Final answer:
At an open intersection, the car on the left should yield to the car on the right, following the universal "right of way" traffic rule to prevent accidents and maintain road safety.
Step-by-step explanation:
When two cars reach an open intersection at the same time, the car on the left must yield to the car on the right. This rule is commonly known as the "right of way" rule and is a fundamental aspect of traffic law designed to prevent accidents at intersections. It is important to be aware of this rule, as it helps to provide order on the road and ensure the safety of all drivers and pedestrians.