Choosing the right clothing is as important as choosing the right bike. Your life may depend on it! Thermal control is the key to safety and comfort whether you're patrolling in the heat and humidity of high summer or the cold and wet of winter.
Your shirt should be made of a material that wicks moisture away from your body. If possible, during the summer wear light colors. Without this thermal control you risk hypothermia which lurks around every bend in the road.
Shorts and patrol pants should permit freedom of movement, yet should conform to the body. They must not bind and confine, however, neither should they flap around to get caught in pedals or spokes when you're whipping down the road on the way to a crime scene. Modern materials that wick moisture away from the body and dry quickly will serve you well.