Decatur’s portable OnSite 350 and 400 units are supported by the new SI3 system, a compact directional antenna for measuring traffic approaching the trailer that interfaces with the flashing display to alert drivers when they have exceeded the speed limit. OnSite trailer options include solar panels, anti-theft alarms, EZ Stat traffic analysis software, red LED violations flashers, and a safety strobe that mimics photo capture of speeding vehicles. The OnSite 400 also features a scrolling message board for communicating with drivers.