The final type of user identified to use this type of system would be that of emergency medical personnel. This type of user differs greatly from that of the other two categories in that this type of personnel are very often employees of private companies/organizations and are not directly associated with the local governments. Addtionally, the types of personnel that would benefit from this type of system would be wide ranging, from doctors and nurses, to ambulance personnel. As a result of this, these users must be able to user hardware that is widely available. In most cases a company would be unwilling or unable to provide the emergency medical personnel with the same level of hardware found in a police cruiser. To address this issue, it has been decided that these individuals can use mobile phones and personal digital assistants (PDAs) equiped with HTML 4 compatible browsers. The primary user in this category would be ambulance personnel. Since it is expected that there will be at least one care giver in addition to the driver, using a mobile phone to transmit the data to them is a feasible means of communicating the state of the system. This type of adaptation requires explicit requests to update the information since wireless handhelds have limited band width in addition to air-time charges that may apply. Additionally, to adapt to the severely restricted space available on wireless handheld screens, text only is sent to these devices. The information included on this type of device is the estmated delay and estimated time until block for each of the railroad crossings in question.
In all of these cases, once common requirement becomes apparent. The users of this system have other things to worry about other than operating this system. The system should be as transparent to the user as possible. As such, the adaptations that take place are typically a result of a single user action than then cascades down to adapt the media to the device and audience that needs to diagest it. For this system to be successful, it needs to provide the persons with the information they need with as little interaction as possible. No matter what their role, they have a common goal of saving lives, and this system should support that goal, not hinder it, or even worse, create a greater lose of life by intruding in on the concentration that had previously been reserved for the job at hand. The nature of this adaptive media system is to adapt to not only the device on which the media is displayed, but also the environment in which it must be absorbed. In the case of the mobile phone or PDA interface which is the most interactive by not providing automatic updates, and only being in text to accomodate the device limitations, the risk of loss of concentration by the driver is mitigated through the expectation that multiple people will be in the ambulance and will be able to provide the driver with the information he or she needs to route a quick course to the emergency scene or to medical care center.