What ISO did you shoot these at? I can't really tell, but the bottom photo looks just a tiny bit noisy. If you can lower your ISO and make your aperture as small as it can go, you can use a longer shutter speed and get more light trails so they are solid throughout the entire photo, instead of stopping short in places, like the car on the on-ramp. That much said, I like the trails. Nice shots!
Try a lower iso and a higher f/stop. On the busiest street in the business area of the town I live, I can get 30 second exposures on the smallest aperture, which I think was f/22 on the lens I was using.
those are really good, though. I wish we had busier traffic here