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31 2nd Street at Adams Street, Coquille, Oregon In Coquille, Oregon, in 2006, the intersection of 2nd Street and Adams Street--a four-way stop-controlled intersection-- was modified from an all-red flashing signal to an IPM system stop-bar application with lighted stop signs on all approaches (see Figure 28). The IPM system and stop signs for any approach illuminate when a vehicle is detected traveling at least 5 mph approaching the intersection. Challenges to successful IPM system operation in stop- bar applications include sensor failure and adherence to the pavement. Marker adherence issues have been attributed to fully loaded logging trucks running directly over the light systems in Coquille, Oregon (unnamed city staff member, personal communication, July 23, 2007). Despite these issues, FIGURE 27 Tunnel IPM system application (milled pavement the IPM system is viewed as beneficial, enhancing the visibil- view), between Newhalem and Diablo, Washington ity of the four-way stop control. Both daytime and nighttime (Courtesy: WSDOT). operations are considered to be effective. The system cost was approximately $40,000; maintenance is covered under a manufacturer warranty. markers hinder their visibility over time. To date, there have been no reported failures with the markers or system. Failure detection does not occur automatically, but is detected through West Alabama Street at the Galleria inspection by the WSDOT maintenance crews or through Shopping Mall, Houston, Texas motorist notifications. The total system cost was estimated as $100,000. Ongoing annual costs associated with system Under FHWA's experimental designation, an IPM system maintenance are approximately $1,000. The operation and was implemented at a signalized pedestrian crossing that safety of the facility have improved with the addition of the connects two sections of the Galleria Mall at West Alabama IPM, WSDOT believes, although no formal evaluation is Street. The IPM system is illuminated during the yellow available (G. Baghai, personal communication, Aug. 37, and red phases of the traffic signal and matches the signal's 2007). color indications. The markers used in this application have five amber LEDs and five red LEDs. When the traf- fic signal provides a yellow indication, the amber LEDs REGULATION illuminate in a steady-burn state (see Figure 29). When the traffic signal provides a red indication, the red LEDs illu- IPM systems have been implemented in combination with minate, also in a steady-burn state (see Figure 30). When other regulatory devices at intersection stop bars and for left- the traffic signal shows a green indication, the IPM system turn restrictions to enhance regulation of road users. is deactivated. Intersection Stop Bars IPM systems implemented at intersection stop bars can be in- tegrated with traffic signals or other control devices to en- hance regulation of road users. Disneyland Drive near Disneyland Resort, Anaheim, California An IPM system intersection stop-bar application on Disney- land Drive in Anaheim, California, was credited with reducing crashes from 14 in a six-month period prior to implementa- tion to 6 in the six-month period following implementation. The system was also credited with reducing red light run- ning and increasing stop-bar adherence (Kaku Associates, FIGURE 28 Intersection stop-bar IPM system application, Inc. 2002). Coquille, Oregon (Courtesy: LightGuard Systems, Inc.).

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32 to better determine lasting system effects over time (TEDSI Infrastructure Group 2004a, b). When compared with the "be- fore" conditions, the following changes were observed after IPM system implementation: Pedestrian compliance with the signal increased by 17% initially following implementation and by 19% follow- ing extended implementation. Motorist noncompliance with the signal decreased by 23% initially following implementation and by 25% following extended implementation. Red-light running decreased by 50% initially follow- ing implementation and by 77% following extended implementation. Stop-bar violations (i.e., the number of vehicles en- croaching over the stop bar) decreased by 6% initially FIGURE 29 Stop-bar application Amber Phase, Alabama following implementation and by 26% following ex- Street at Galleria, Houston, Texas. tended implementation. Initially there were problems with electrical "shorts" in the Note that in each case the IPM system effectiveness was ob- IPM system; however, this was attributed to initial system served to increase rather than decrease over time, although wiring rather than equipment failure. Once resolved, few the time period for measurement following extended imple- additional maintenance issues were reported. As with other mentation was not reported (e.g., three months, six months, applications, it was noted that the IPM system markers do and one year). collect dirt and debris and require occasional high-pressure water cleaning (tunnel-like conditions under the pedestrian bridge prevents rain from self-cleaning the markers) (R. Taube, Various Locations along METRORail Line, personal communication, July 23, 2007). Decreased lumi- Houston, Texas nous intensity was also noted with the IPM system markers. This is likely attributable to the reduced number of LEDs per In 2006, The Houston Metropolitan Transit Authority of Harris illumination phase (i.e., 5 yellow or red LEDs per illumination County, Texas (METRO) implemented an IPM system at an in- rather than the more typical 10). The total cost for this IPM tersection stop bar in the Houston central business district, system was approximately $45,000, comprising material costs specifically at the intersection of Jefferson Street and Main of $30,000 and installation costs of $15,000 (P. English, per- Street (see Figure 31). Only the Jefferson Street approach was sonal communication, July 23, 2007). The effectiveness of initially equipped with the IPM system. Jefferson Street is a the IPM system at this location was measured at two different five-lane, one-way, eastbound street that intersects the times following implementation: (1) initially following system METRORail line at Main Street. The motivation for this im- implementation, and (2) following extended implementation plementation was to increase road user awareness of the traffic FIGURE 30 Stop-bar application Red Phase, Alabama Street FIGURE 31 Intersection stop-bar IPM system application, at Galleria, Houston, Texas. Jefferson Street at Main Street Houston, Texas.

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33 signal and the onset of a red indication, to subsequently reduce showed a minor reduction in red-light running (from 9 per the incidence of red-light running on streets intersecting the rail day to 8 per day), but a major reduction (more than 50%) in line. The Jefferson Street approach served as the initial test site. right-turn-on-red maneuvers (from 47 per day to 18 per day). Similar findings were observed when these changes were The IPM system at this location is configured in a linear normalized to reflect violations per 1,000 cycles or violations layout with two offset rows of red LED markers. The spacing per 10,000 vehicles (Tydlacka and Voigt 2006). of IPM markers in each row is approximately one foot, but the offset of the markers between the two rows effectively Crash frequency was also monitored before and following presents a six-inch spacing. The IPM system is activated in a IPM system activation. One year of crash data before IPM steady-burn state when the eastbound traffic signal indica- system implementation and six months of data following im- tion for the Jefferson Street approach changes to red. The IPM plementation were considered. A reduction from two to zero system is deactivated when the traffic signal operates in an eastbound crashes was observed after the IPM system was all-red flashing mode. implemented. The short observation period and infrequent crash occurrence limits further conclusions related to the This IPM system uses an inductive loop power source, crash reduction potential of the IPM system at this site. These eliminating the need for the markers to be hardwired directly findings related to driver comprehension, traffic operations, to the power source. The installation of the system involved and vehicle crashes at Jefferson Street are preliminary but cutting a groove in the pavement to place the inductive power promising. Evaluations are still ongoing. loop, coring the pavement to install the power nodes, and ad- hering the markers to the pavement surface above the nodes. Given the promise of the initial IPM system at Jefferson Street, a second street that approaches Main Street--Gray Reported issues with the performance of this IPM system Street--was equipped with an intersection stop-bar IPM sys- include a lack of marker adherence to the pavement (i.e., a tem at Main Street. This intersection was also equipped with high frequency of pop-offs) and a loss of luminous intensity LED-bordered backplates installed behind the traffic signal over time (W. Langford, personal communication, 2007). faces. Figure 32 depicts both the IPM system intersection stop-bar application and the LED-bordered backplates. When As with the IPM system application at West Alabama the traffic signal indication changes to red, the IPM system Street at the Galleria Shopping Mall in Houston, Texas, the and the LED-bordered backplates are concurrently illuminated Jefferson Street at Main Street IPM system was deployed with in a red, steady-burn state. Evaluations of the effectiveness of FHWA's experimental approval. As part of this process, semi- these combined systems are ongoing. annual reports are required to document the effectiveness of the application under experiment. The first report provided in- Most recently, Houston METRO has implemented sev- formation on driver comprehension, traffic operations (includ- eral additional IPM systems at intersection stop bars (as well ing red-light running and violations of the right-turn-on-red as LED-bordered backplates) along Main Street and the light prohibition), and vehicle crashes (Tydlacka and Voigt 2006). rail line. Two different types of IPM systems were used across these locations, requiring different installation techniques, Driver comprehension studies were conducted in April power delivery methods, and operating modes (i.e., flashing). 2006 with 103 individuals who drive in and around Houston and specifically, along the METRORail line. The partici- pants were shown a selection of video clips (some of which contained computer-animated renditions of the proposed in- tersection stop-bar IPM system application in the active state) and asked to complete a survey after viewing the videos. These comprehension studies were completed before the IPM system was activated in the field. The driver com- prehension studies showed that nearly 90% of respondents stated that the first characteristic they noticed about the in- tersection was the IPM system at the stop bar. More than 80% believed that the purpose of the system was to tell driv- ers where to stop for the traffic signal. It was concluded that most drivers noticed the IPM system and associated the IPM system with the traffic signal (based on computer-animated renditions of the proposed IPM system). The initial operational analysis was supported by three FIGURE 32 Intersection stop-bar IPM system with days of data prior to IPM system implementation and one day LED-bordered backplates, West Gray Street at Main Street, of early "after" data following implementation. The results Houston, Texas.

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34 One of the IPM systems is designed such that each marker flashes consistently, but individual markers flash with left and right sides alternating. Table 4 summarizes current inter- section stop-bar IPM system and LED-bordered backplate applications currently in use by Houston METRO. Left-Turn Restrictions Left-turn restrictions are typically conveyed to road users through static regulatory signing. IPM systems have the poten- tial to enhance road user awareness of turn prohibitions, and offer more flexibility in operations related to time-of-day or transit-priority restrictions. Various Locations along METRORail Line, FIGURE 33 Active "X" for do not enter left turn lane on X, Houston, Texas Houston, Texas (Courtesy: Houston METRO). A segment of Houston's METRORail light rail is centered on Fannin Street running in the former median portion of the road- mounted dynamic signs are linked to the traffic signal con- way. Along this corridor, left-turn movements are prohibited troller. When a train approaches from either direction, the in both northbound and southbound directions along Fannin "Green Arrow" is replaced with a "Red X" and the "Train Ap- Street (within the Texas Medical Center) when a train is ap- proaching" sign is illuminated ("Walking . . ." 2007). proaching. Despite this left-turn restriction, a number of crashes have occurred involving left-turn movements by road users. To To supplement this dynamic lane control assignment sys- reinforce the turn restriction, Houston METRO first installed a tem, Houston METRO in 2006 implemented an IPM system dynamic lane control assignment system (see Figures 3335). on the northbound and southbound approaches of Fannin A "Red X" indicates that left-turn movements are prohibited; Street at Dryden Street (see Figures 36 and 37). a "Green Arrow" indicates that left-turn movements are allowed and a "Train Approaching" sign provides additional warning to A single row of red IPM system markers is placed along road users ("METRORail . . ." 2007). These overhead- the lane line between the left-turn lane and the left through TABLE 4 INTERSECTION STOP-BAR IPM SYSTEMS AND LED-BORDERED BACKPLATES IN HOUSTON, TEXAS IPM Location Along Main Street System LED Backplates Implementation Date Jefferson Street (eastbound) March 2006 (IPM System) August 2007 (LED Backplates) Gray Street (westbound) October 2006 (IPM System) June 2007 (LED Backplates) McGowen Street (east/westbound) November 2006 Webster Street (eastbound) February 2007 Dallas Street (eastbound) May 2007 Commerce Street (westbound) June 2007 Walker Street (westbound) June 2007 Elgin Street (east/westbound) June 2007 Alabama Street (east/westbound) June 2007 Pierce Street (eastbound) July 2007 (IPM System) February 2007 (LED Backplates)

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35 IPM (Not Active) FIGURE 34 Active "Arrow" for permitted access left-turn lane, FIGURE 36 Left-turn restriction IPM system application Houston, Texas (Courtesy: Houston METRO). (not active), Houston, Texas. lane in both the northbound and southbound directions. The As with the previous IPM system applications in Houston, markers are spaced approximately 5 ft apart and extend from Texas, this IPM system was implemented with FHWA's the beginning of the left-turn bay through the Dryden inter- experimental approval. As part of this process, semi-annual section. The system is activated in a steady-burn state when reports are required to document the effectiveness of the appli- the dynamic lane control assignment indicates a "Red X." cation under experiment. The first report provided information on driver comprehension, traffic operations (including viola- The installation of the system involved cutting a groove in tions of the prohibited left-turn maneuver), and vehicle crashes. the pavement to place the inductive power loop, coring the pavement to install the power nodes, and adhering the mark- Conducted simultaneously with the previously described ers to the pavement surface above the nodes. driver comprehension studies for IPM system intersection stop-bar applications, the driver comprehension studies for Not unique to this application, power supply issues were this application were conducted in April 2006 with 103 indi- encountered early in IPM system operation but have since viduals who drive in and around Houston and, specifically, the been resolved. On more than one occasion, the system was Texas Medical Center. The participants were shown a selection without power owing to a suspected manufacturing defect in of video clips (some of which contained computer-animated the power supply. Also, marker adhesion has been problem- renditions of the proposed IPM system in the active state) atic; some markers were dislodged from the pavement and and asked to complete a survey after they viewed the videos. were lost or destroyed by traffic. Once the missing markers These comprehension studies were completed before the IPM were replaced with stronger adhesive, the system has oper- system was activated on Fannin Street. The results of this ated with few to no problems (W. Langford, personal com- munication, 2007). IPM (Active) FIGURE 37 Left-turn restriction IPM system application FIGURE 35 Train approaching sign (flashes on train approach). (active), Houston, Texas.