Unit 05 Lesson 04 - Single Point Urban Interchanges
Single-point urban interchanges are becoming more common in the construction of freeway interchanges today. It is a type of interchange that is located either above or underneath the freeway and is designed in such a way that the intersecting off-ramps and on-ramps are diagonally adjacent to each other.
These interchanges can be confusing. However, there are some things that may help drivers when passing through a single-point urban interchange. Dash lines have been added to these interchanges in an effort to guide drivers into the proper lanes. There are also “wrong way” signs placed on the off-ramps and on-ramps to help drivers avoid entering a ramp against traffic.
It is legal to make a U-turn from the off-ramp at a single-point urban interchange and re-enter the freeway, as long as you are facing a green arrow at the time you begin the maneuver. When you re-enter the freeway on the on-ramp, you will be facing a red arrow. The red arrow is intended for the traffic adjacent to the light. Do not stop your vehicle in the middle of the intersection; complete the maneuver once it is initiated.
If a power outage occurs, the single point urban interchange is not handled the same way as a four-way stop. It is important to proceed with extreme caution and courtesy. Most single point urban interchanges will be supported by battery back-up. However, if a situation occurs where there is not a battery back-up, an officer will be dispatched to the scene for the purpose of traffic control as soon as possible.