What kind of antenna do you have?
You should also make it more visible.
I know I keep mine easy to see. I'll either use a 48" black fiberglass, a 54" metal bullwhip, or (the one I usually use) a 26" black fiberglass that I made from a damaged 48", that one works great for parking garages...its a long story about why I made a parking garage safe antenna.
With the little antenna the truck is only about 7 feet tall, 6.5 w/o any antenna. They all sit on a spring to keep them from getting broken which works wonders if you ever get a stiff antenna. They are attached to the truck toolbox with a swivel ball mount that also works really well.