Due to the informal nature of our dress here in California, it seems that baseball caps, t-shirts, fleece jackets, etc bearing a College or University name and/or logo fulfill a similar function to neckties in the UK.

It's very common for people not only to wear such "college gear" but also to fly college flags on their houses.

In many cases parents will wear gear and fly flags of the college/university their child is attending/did attend.

Around here much of this is fueled by the rivalry between the Los Angeles area's two most prominent universities, USC and UCLA.

So a car will have a licence-plate frame that says "MY MAID WENT TO UCLA" and down the street in a posh neighbourhood you might see alternating flags from those two schools interspersed with flags from universities across the country.