Santa Nella is a major crossroads where Highway 152 and 33 and Interstate 5 all connect

 So, for example, if you are in San Jose heading to Interstate 5 south you would likely take 25 to 152 to 33 to Interstate 5 as one example of driving south on 5 towards Los Angeles.

However, if you were headed to Santa Barbara you might take Highway 101 south right now from San Jose because it is just too hot to travel down Interstate 5 right now (from my point of view at least). Also, Santa Barbara is very awkward to get to off of interstate 5 if you look at any map you can see what I mean. So, Santa Barbara from the SF Bay area is more easily and comfortably reached by heading down Highway 101.

However, if you are trying to get to Los Angeles County the best route might be Interstate 5 even though you are going to completely cook right now doing this. So, first make sure your air conditioner in your car is working before you attempt driving down Interstate 5.

Because right now with the heat generally speaking Highway 101 is going to be at least 10 degrees cooler on average all the way from San Jose to Santa Barbara generally speaking partly because parts of the way you are driving along the ocean which is almost always cooler traveling.