Agenda - Council - 07/22/2008 - Laserfiche WebLink

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Table 7. Number of 11Teia~ Messages Seen at Various Driver Speeds anal Time b~.tervals Between Messages Time sign is Speed clearly visible (mph) ~ (seconds) Number of Seen Message Display Time (seconds) 8 10 60 1800 3600 (30 minutes) (1 hour) 30 ' 60 ~ 11 9 7 2 1 1 45 40 8 6 5 2 1 1 55 I 33 7 5 4 2 1 ~l I *Assuming the sign is clearly visible from one-half mile away. Prohibiting displays from changing quickly can minimize potential driver distraction, but it «~ould significantly limit the message owner's ability to convey information that does not fit on one screen of the sign. Using i~~~o or more successive screens to convey a message is referred to as sequencing. Based on the studies summarized in part 3 of this Report, including the glance duration studies perfornned by Klaur for the FHWA in 2006 and by Beijer & Smiley in ?004; and ~Wachte]'s analysis for Seattle of the Zeigaizlik effect, a message delivery system such as sequencing that requires or induces a driver to watch the sign for several seconds increases the likelihood of driver distraction. Based on information from the sign industry, for sequencing to be effective in a marketing sense; a brief rate-of-change (1-2 seconds) is generally used before transitionizg into the next screen. Some codes specify how an image changes; while other codes prohibit the use of transitions. The change from one image to another can be accomplished by various techniques: no transition - simply a change from one screen to another; or fading or dissolving one image into the next. Flashing, spinning, revolving, or other more distracting transition methods can be prohibited, allowing businesses to use sequencing in an .effective manner without making the signs overly distracting. Another way of regulating distracting transitions is to require a very short time of a dark or empty screen bet«~een images. 4.2.4 Motion. Animation, or Video Limitations on Electronic Sims Motion on a sign can consist of everything from special text effects (spinning; revolving; shaking, flashing, etc.) to simple b •aphics; such as balloons or bubbles rising across the screen, to more realistic moving images that have the appearance of a television screen. Accordung to sign industry representatives, video imagery on a -sign is referred to as "animation" if the sign is 1umited to 'the capability of 10 frames per second. Fewer frames per second make the moving image look more like animation. Imagery produced by signs that have the capability of processing up to 30 frames per second is accurately referred to as "video'' imaging. Many communities that allo~~~ dynamic signs do not alloi~~ the application of any type of motion; animation; or video on the signs. However, Seattle was obliged to allo«~ video imagery on their signs after earlier signage code regulating certain types, of signs was not strictly enforced. In .addition to requiring a dark period bet«~een successive messages to overcome the Zeigainik effect; Seattle also limits the duration of the video message to a minimum of t~~-o seconds a11d a Q24 -232-