The OnSite 350 and OnSite 400 speed-message trailers are durable and high-quality trailers that offer economical traffic speed monitoring and control measures. They may be equipped with various options depending on traffic and budget needs of small, medium and large-sized police departments. The portable Onsite 350s and 400s may be moved easily to one or more locations and are supported by Decatur's latest radar technology - the new and upgraded SI3, system interface. The SI3 is a more compact directional antenna for measuring traffic approaching the trailer. It 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 unit also features a standard scrolling message board that can be used to communicate messages to drivers.