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13 FIGURE 2 Retractable barriers under test in Wayne County, Michigan (Courtesy: Michigan Department of Transportation). the FHWA, are currently testing a type of retractable barrier Active Train-Approaching Warning Signs to discourage drivers from driving around the crossing gates at a crossing in Wayne County (9). The delineators Active train-approaching warning signs supplement the turn are activated by a signal from the crossing gate system and arrow signal indication, which serves as the primary regulatory reach their full deployment in about 6 s (Figure 2). Metro in control device at the intersection. These active signs warn Los Angeles is interested in the possible trial application motorists of the increased risk associated with violating the of these same retractable barriers across the far side of the turn arrow signal indication (1). Transit agencies have imple- marked crosswalk to block the left-turn pocket lane. Los mented a variety of active "train-approaching" warning signs, Angeles noted a number of potential issues with this appli- ranging from the use of pedestrian heads that display the cation, including interaction of the delineators with pedes- words, "TRAIN" or "TRAIN COMING," to the use of the trians in the crosswalk, vehicles encroaching into the cross- W10-7 (Light Rail Transit Approaching) LRV-activated flash- walk, life expectancy of the delineators with the number of ing blank-out signs suggested in the Manual on Uniform Traf- up-and-down cycles required for light rail operations, and fic Control Devices for Streets and Highways (MUTCD) (10) failure of the delineators. (Figures 3 through 5). LACMTA uses the MUTCD sign, but supplements the LRV icon with the word "TRAIN" (Figure 6). TRAFFIC SIGNS In most applications, the icon sign flashes to draw more attention from motorists. Some agencies even use a varia- McCormick and Sanders (cited in reference 3) noted that most tion of the orientation of the LRV icon depending on which linguistic research indicates that active, affirmative statements approach the sign is targeting. For example, in Portland generally are easier to understand than passive or negative (Oregon), motorists in the left-turn pocket lanes see an icon statements. In addition, Whitaker and Stacey (cited in refer- portraying the front of an LRV, whereas motorists on the ence 3) found that permissive stimuli (e.g., "do") produced cross-street approach to the tracks see an icon portraying the faster responses than prohibitive stimuli (e.g., "do not"). In the side or profile view of an LRV. The orientation of the LRV METRORail Traffic Safety Assessment (4), it was noted that icon is meant to provide additional directional information to the traffic control devices in use placed an emphasis on pro- the motorists. At some agencies, these signs have evolved over hibited rather than permitted movements and the possibility of the years depending on current practice and available funding. driver confusion about where turns were allowed and where Many transit agencies, including TriMet, Houston METRO, through movements were the only permitted movements. The and LACMTA have found these signs to be an effective means recommendation to METRO was displaying permitted move- ments provides positive guidance, which could ease decision load on drivers and could result in fewer last-second decisions in complex driving conditions. Specific recommendations for signage included · Overhead lane-use control signs in place of extra turn- prohibition signs; and · (Turn) ONLY signs where there was only one permit- FIGURE 3 MUTCD W10-7 (Light Rail ted movement at an intersection. Transit Approaching) sign.
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14 FIGURE 4 Train-activated warning sign--Hiawatha Line, Minneapolis (Courtesy: Calvin Henry-Cotnam). FIGURE 6 Train-activated warning sign in Los Angeles. of reducing left-turn collisions. Newer LRT systems have pedestrian heads to display the words, "No Left Turn," to benefited from the use of these signs by older LRT systems the use of the "No Right/Left Turn Across Tracks" activated and have incorporated the latest technology into their systems' blank-out signs suggested in the MUTCD (R3-1a, R3-2a designs. signs shown in Figure 7) (10). To restrict turns when an LRV is approaching, some agencies use the activated blank- Active turn-prohibition signs are generally used where left out versions of the MUTCD no right- or left-turn symbol and right turns are permitted across the tracks except when sign (R3-1/R3-2) shown in Figure 8, as was recommended an LRV is approaching. Transit agencies have implemented a in TCRP Report 17 (1). Sacramento RT formerly used acti- variety of active turn-prohibition signs, ranging from the use of vated blank-out signs with the words, "No Left/Right Turn." Currently they use the activated blank-out versions of the R3-1 and R3-2 symbol signs, as shown in Figure 9, which they believe work better than the text versions of the signs. METRO in Houston uses no right- or left-turn activated blank-out symbol signs that incorporate the tracks symbol, as illustrated in Figures 10 and 11. FIGURE 7 MUTCD R3-1a and FIGURE 5 Train-activated warning sign in Houston. R3-2a signs.
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15 FIGURE 12 MUTCD overhead lane-use control signs. Overhead Lane-Use Control Signs FIGURE 8 MUTCD R3-1 and R3-2 signs. Where motorists make left turns from the wrong lane (usually in the case of mixed-use operations), the use of overhead lane- use control signs can provide positive guidance and can indi- cate the allowable movements from each lane. The lane-use signs can be supplemented with the word ONLY when only one movement is permitted from the lane. Figure 12 shows the use of the MUTCD overhead lane-use control signs R3-5 (through-only) and R3-5a (left-turn only). Figure 13 shows the use of an overhead lane-use control sign in Houston, which incorporates the tracks symbol. Overhead advance intersection lane-use control signs can also be used to provide advance warning to motorists (4). FIGURE 9 No right-turn activated blank-out sign in Sacramento Use and Placement of Static Signs (Courtesy: Sacramento Regional Transit District). Signalized intersections that incorporate LRT by design are complex intersections. When a multitude of signs are present at these intersections it can cause visual clutter, increase driver information processing time, and increase the potential for missing important information regarding permitted or prohib- ited movements and LRT presence. Consolidating traffic sign messages where possible and eliminating unnecessary redun- dancies can reduce the visual clutter as well as the chance of driver error (4). One way to reduce the number of signs placed FIGURE 10 No left-/right-turn-activated at the intersection is to use the MUTCD combination "No left- blank-out signs with tracks symbol turn/No U-turn" symbol sign (R3-18) instead of two separate (Courtesy: Metropolitan Transit Authority of signs (Figure 14). Harris County, Texas). FIGURE 11 No right-turn-activated blank-out sign with tracks FIGURE 13 Overhead lane-use control signs in Houston symbol in Houston. (Courtesy: Houston METRO).
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16 FIGURE 16 Use of the MUTCD No Turns sign. FIGURE 14 Combination no left-turn and no U-turn sign section, the gates remain down as the second train passes (MUTCD R3-18 sign). through the crossing; however, if the first train has finished crossing the intersection, the presence of the second train causes the gates to come back down before reaching their full Sign placement can also help motorists focus on the vertical position (11). information that is intended for them. For example, left- and U-turn-prohibition signs should be placed in the median, As part of a demonstration project sponsored by TRB, the on the far-left side, or on the left side of the signal mast arm Maryland Mass Transit Administration (MTA) tested a sec- (not on the right side of the intersection). Figure 15 shows an ond train coming warning sign. The active sign flashed the example of the No U-turn sign placed over the far-right lane word "WARNING," which was followed by a steady appear- of traffic and where the combination No left-turn/No U-turn ance of the words, "2nd Train Coming," which was followed sign would be appropriate to reduce sign clutter. Likewise, by an animation of an LRT moving through a crossing (see right-turn-prohibition signs should only be placed on the right Figure 17). This display was supplemented with flashing bea- side of the intersection. When both right and left turns are pro- cons to attract motorists' attention to the new sign (11). hibited at an intersection, the MUTCD No Turns sign (R3-3) The sign was mounted on the cantilever arm at a heavily trav- can be placed on the signal mast arm (4) (Figure 16). eled highway rail intersection where trains operate at a speed of 50 mph. Risky behaviors were observed during a period before the sign was installed and during two periods after the Second Train Coming Warning Sign sign was installed. Overall, the findings demonstrated that One of the most challenging aspects that the Baltimore LRT during the second 30-day period after the sign was installed, system experienced after start-up was the "second train com- less risky behavior was observed than during the first "after" ing" phenomenon that occurs on double track crossings. This period. A significant reduction of 26% was noted in the fre- phenomenon occurs when two trains traveling in opposite quency of vehicles that crossed the tracks after the first LRV directions activate the crossing equipment within seconds of cleared the crossing while the gates were ascending but had each other. If the first train has not finished crossing the inter- not reached the full upward position, and before the gates descended again on activation of the circuits by the second train. However, it was still observed that the majority of drivers attempted to travel through the crossing as soon as the gates began to ascend, with or without the indication of a second train coming. Left Turns Can Be Accomplished by Making Signs Showing Three Consecutive Right Turns In addition to the signs used by transit agencies to mitigate col- lisions between LRVs and motor vehicles, the Texas Trans- portation Institute (TTI) recommended that Houston METRO make use of signs showing that left turns can be accomplished FIGURE 17 Second train coming warning sign (Courtesy: Ziad FIGURE 15 Example of sign clutter and misplacement. Sabra, Sabra, Wang and Associates, Inc.).