Fremontodendron. A great native crossed with something..to get more blooms over a longer season. Once its going? It need no summer watering.

[Photos appeared with second viewing]

Ken Taylor is an example of a fremontodendron hybrid (F. decumbens and F. californicum), but not all of the fremontidendrons grown in gardens are hybrids. With the height and clear yellow flowers, you might want to also consider F. californicum.

Thank you! I've been driving past this tree for 4 years now and never noticed it before. 15-20 feet tall and gorgeous

Not thorny but all parts coated with readily detached, irritant hairs - hence, presumably Flannel Bush. And surely making the planting location not the best in this instance.