Highway Resource Solutions (HRS) has introduced an integrated road safety solution known as Intellicone on parts of the M6 motorway in the UK. Intellicone alerts road maintenance personnel and workers to the danger of an approaching vehicle. The system has a wireless sensor network consisting of impact sensors that transmit alarm signals to the Intellicone Portable Site Alarm (PSA) in response to an accident. The alarm signal in turn activates an audio-visual crew alarm. Each alarm has a short-range RF transceiver for two-way communications and a GSM system to provide user text messages. It also has a GPRS system for long-range communication between alarms.