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36 study indicated that approximately 82% of the respondents ILLUMINATION understood the meaning of the IPM system to be "do not enter the left lane." Only 50%, however, thought that the IPM With a primary intent to provide an alternate source of illu- system signaled that a train was coming. Respondents were mination, IPM systems have been implemented at vehicle also shown an image with the IPM system and an overhead and truck inspection points and in environmentally sensitive "Train Approaching" sign, yet 18% did not include "a train areas, potentially affected by light pollution attributable to is coming" or "do not turn left" in their response. The driver conventional overhead roadway lighting systems. comprehension study concluded that although most drivers understood that the purpose of the IPM system was to restrict Vehicle and Truck Inspection Points access to the left-turn lane, some road users may be chal- lenged to determine when a train is approaching or when they At locations where safety and security is of heightened con- are allowed to enter the left-turn lane using the current dy- cern (e.g., international border crossings and military facili- namic lane control assignment and IPM system. ties), IPM systems have the potential to enhance the monitoring capabilities of officials at these locations through improved The operational analysis for this combined dynamic lane illumination. control assignment and IPM system application considered five specific violation types: Vandenberg Air Force Base, Santa Barbara 1. Type 1 LT Violator--Vehicle enters left-turn lane County, California against the "Red X" of the dynamic left-turn lane con- trol signal and completes left turn. Because of their upward light projection, IPM systems have 2. Type 2a LT Violator--Vehicle completes left turn from been used by monitoring inspectors to better view the under- lane other than left-turn lane against the "Red X" of the carriages of entering and exiting vehicles (see Figure 38). dynamic left-turn lane control signal. Most contacts interviewed for this synthesis effort declined 3. Type 2b LT Violator--Vehicle completes left turn from to divulge details about these systems for security reasons; lane other than left-turn lane with the "Green Arrow" a representative from Vandenberg Air Force Base did con- of the dynamic left-turn lane control signal. firm the use of IPM systems at two different locations. No 4. LT Violator/Bailout--Vehicle enters left-turn lane additional information regarding the installation, operation, against the "Red X" of the dynamic left-turn lane con- maintenance, cost, or effectiveness of these IPM systems was trol signal and does not complete the left turn. available. 5. Bailout--Vehicle enters the left-turn lane legally with the "Green Arrow" of the dynamic left-turn lane con- Environmentally Sensitive Areas trol signal and does not complete the left turn, contin- uing straight on Fannin Street. Light pollution, attributable to conventional overhead roadway lighting systems, has prompted the use of IPM systems as an Three days of data prior to IPM system implementation and alternative source of illumination at a number of locations one day of early "after" data following implementation sup- deemed to be environmentally sensitive. ported this operational analysis. The results showed a consis- tent trend in violations; total violations were either the same or slightly higher than before when measured shortly after im- plementation. The number of Type 1 violators (i.e., vehicle en- ters left-turn lane against the "Red X" of the dynamic left-turn lane control signal and completes left turn) per 10,000 vehicles was observed to decrease, however, for each direction. These results should be viewed as preliminary and should take into account the short observation period (i.e., one day) following IPM system implementation (Tydlacka and Voigt 2006). The crash analysis at this site was inconclusive owing to an infrequency of observed crashes (no left-turn vehicle/train crashes occurred at this location in the year before IPM system implementation or in the six months following implementa- tion) and the abbreviated observation period following IPM system implementation. Although no significant reduction in crashes could be attributed to IPM system implementation at this site, left-turn vehicle/train crashes have shown a consis- FIGURE 38 Vehicle and truck inspection point IPM system tent annual decline over time. application (Courtesy: Traffic Safety Corporation).
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37 SR A1A, Boca Raton, Florida Two separate studies were done by the University of Florida to determine the effectiveness of the combined bol- In Boca Raton, Florida, sea turtle hatchlings are instinctively lard lighting and IPM systems, considering both the turtle drawn to the ocean by the reflection of light from the sky on hatchlings and the general public. The hatchlings study re- the water's surface. Along State Route A1A, the installation vealed a 99% decrease in hatchling disorientation attribut- of overhead artificial roadway lighting confused the hatch- able to the alternative light system. In the public acceptance lings, drawing them inland (instead of toward the ocean) study, the majority of the public was in favor of the project where they became dehydrated, preyed upon, and even run and agreed that the alternative light system was adequate for over by vehicles. In 2001, FDOT initiated an experimental roadway usage. Older road users, however, were observed to demonstration project to test the use of IPM systems as an al- be less receptive to the alternative light system. No changes ternate illumination source with the intent of preserving the in crash characteristics were observed as a result of the alter- sea turtle hatchlings (see Figure 39). native lighting (Ellis and Washburn 2003). A one-half-mile section of SR A1A, adjacent to the beach and the city's Spanish River Park, was selected as the demon- N513 Highway, Castricum, Province stration site. The existing overhead roadway lights were deac- of Noord-Holland, the Netherlands tivated and combined bollard lighting and IPM systems were implemented. The alternative light sources were physically Along the N513 Highway in the Province of Noord- lower in height than the sea dunes adjacent to the roadway to Holland, the Netherlands, an IPM system was implemented prevent light from reaching the beach. The alternate light sys- as an alternative to overhead roadway lighting to address tem is only used during the sea turtle mating season (from May safety concerns in an environmentally sensitive location. to October), and is photo-sensitive, illuminating at dusk. At this location, bicyclists returning from the adjacent beach and conservation area frequently cross the N513 Not unique to this application, marker adhesion was re- highway. The proximity of the conservation area pre- ported as initially problematic at this location; the adhesive cluded use of conventional overhead roadway lighting to used to hold the markers in place would release in Florida's increase the visibility of the bicyclists as they crossed the high summer temperatures. This issue was fully resolved by the highway. manufacturer. The control cabinet was also struck by lightning and has since been replaced with a stronger, grounded box. In 2003, solar-powered IPM system markers were placed along the centerline of the roadway for a distance of approx- Although no IPM system costs were directly reported, imately 180 ft on both sides of the bicycle crossing (see Fig- a resurfacing project is planned for SR A1A that will pro- ure 40). Inductive loops are used to activate the IPM system vide continued use of the existing half-mile IPM system and as vehicles approach the crossing area. extend the system for an additional half-mile. The cost of the combined resurfacing/IPM system project is $500,000 The Dutch reported a 99.2% savings in energy and minimal (A. Broadwell, personal communication, July 26, 2007). impacts on wildlife as a result of the IPM system. In addition, no fatalities or injuries have been reported since the installation of this system. No information was provided, however, re- garding safety levels before IPM system implementation to FIGURE 39 Environmentally sensitive area IPM system FIGURE 40 Environmentally sensitive area IPM system application SH A1A Boca Raton, Florida (Courtesy: SmartStud application, Province of Noord-Holland, the Netherlands Systems). (Courtesy: Astucia Traffic Safety Systems).