Can you get reflective tights ?

You’re right. Its often the legs which are visible because of the movement. Your running shoes should create some reflection. Most brands produce very reflective shoes which work well. The other thing you could try are the bands that clip around you legs. Perhaps get a couple and put them around your ankles.

As for tights themselves, I don’t know any that would meet your description. The main source of reflection apart from the lower leg is usually the upper body. Reflective running jackets are relatively inexpensive if you go for the less-well-known-brands and obviously cover a big area of your body.