What is the function of the interchange that is located at the junction of Interstates 680, 280, and 880? When California drivers are backed up in traffic, it is not unusual to hear them pose questions of this nature to one another.
Having said that, the only thing you need to know about the closeness of the 405 and 805 to the I-5 may be the number of people you’ll need to fit in your carpool lane.
Chapter 20 of the Highway Design Manual was where we were directed to go by Caltrans. You will discover in that part that the important north-to-south routes of the Interstate Highway system are given odd numbers as their route designations. In most cases, there are an even number of people on our east-west routes. These three-digit subsidiary highways, the most of which are just a few miles in length, take their names from the larger thoroughfares to which they are connected.
In other words, the 405 and 805 got their names from the I-5, which is where they split off from, and the 710 got its name from the I-10, which is where it joins up with.
