Numerous tests and investigations are being conducted to determine the exact nature of the failure.  The results of these investigations might lead to new maintenance and/or inspection techniques to prevent future tragedies.   One thing that is obvious to all in the bridge community is the need for proper maintenance and inspection programs to help prevent more failures from occurring.

• Transmissive
• Reflective
• Transflective

Transmissive screens are found in the vast majority of laptops sold today.  They are optimized for indoor office use and perform very poorly in sunlight.   A transmissive screen has thousands of diodes layered on the screen.   You may see this labeled as TFT  (thin filmed transistor) it might also be called Active Matrix.  By running current through a find grid the pixels can be turned on and off and represent different colors.  The main difference between transmissive and the other two screen types is that to illuminate the LCDs the main power source is a fluorescent backlight.  This fluorescent backlight is optimized to generate enough brightness so that the screen can be clearly seen in indoor lighting environments.  Take it outside on a sunny day and the backlight is quickly overpowered relative to the sunlight and the screen appears washed out.    

Reflective screens are billed as the outdoor solution to this problem.   Instead of using a backlight to illuminate the LCDs they utilize mirrors that reflect the natural light hitting the screen back through the LCDs.  Thus, the stronger the sunlight hitting the screen the brighter the screen.  A major advantage to this approach on laptops is that it prevents the battery from being drained quickly by having to output large amounts of power for the screen.     However, this technology is limited in use and availability since the screens can actually appear rather dim in many indoor office environments or not even be visible when it is used in a dark room.

Transflective screens are commonly used on laptops claiming to be designed for 'outdoors' usage.   Transflective screens are a hybrid that combines the mirror backing of the reflective screens with the fluorescent backing of the transmissive screens.  These screens are ideal for inspectors who want to be able to take their laptops outside and use them indoors.   When inside or in low light environments the backlight automatically illuminates the screen, when outside the reflective mirrors are used to produce an even brighter image and save battery power.  The main drawback is that their dual functionality makes them more expensive and their availability on most laptops is limited.   Due to the additional hardware required often the resolutions and depth of colors are not as great as on similar sized transmissive displays.

When considering a laptop for use by inspectors in the field it is necessary to consider the screen type.  For use in outdoor environments having a transflective screen is recommended and greatly increases the usability of the computer.  Additional factors such as portability of the laptop (weight/dimensions), processor speeds, and memory all combine to produce a machine that effectively enables inspectors to do their jobs.  The common mentality of giving inspectors the 'hand-me down' computers for field use can be one of the worst approaches to take since it can lead to heavy, slower computers with hard to read screens out in the field.  Investing a little extra in quality hardware can lead lead to much happier inspectors and significantly improved results.