What sort of trees are all of those that are planted along the I-5 from southern to northern California?

I drove up to San Francisco from Orange County taking the five and I just loved all of those groves of trees that were all over the place for nearly the whole trip. They had dark bark at the trunk, and then the branches were almost reddish-looking but they turned grey right at the top. They weren't very tall and it was winter so they had no leaves. Any ideas?