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11 CHAPTER THREE COUNTERMEASURES TO MITIGATE COLLISIONS BETWEEN LIGHT RAIL VEHICLES AND MOTOR VEHICLES AT SIGNALIZED INTERSECTIONS This chapter focuses on the countermeasures used to mitigate turn lane directly in front of the first left-turn vehicle collisions between LRVs and motor vehicles at signalized waiting to turn. Calgary Transit has installed both types intersections. According to Coifman and Bertini (3), a counter- of left-turn gates. measure for mitigating collisions between LRVs and motor · Four-quadrant gates--From the review of a variety of vehicles should address motorists' expectations at conventional gates conducted in the FTA study, full-closure, four- intersections as well as work to keep motorists within the law quadrant crossing gates were selected as the best option as at LRT crossings. They go on to state, they offered a number of advantages over the other gate systems reviewed. A full-closure, four-quadrant cross- A successful collision countermeasure should accomplish at ing gate system was installed in October 1998 at the least one of the following goals: 124th Street intersection in south central Los Angeles to deter motorists from making left turns around lowered Remind the driver that there are special risks in the given situation railroad crossing gates. During the experimental phase, Physically prevent the driver from taking these additional data recorded for the first 6 months of operation at the risks (3, p. 4). 124th Street intersection showed that the four-quadrant gate approach resulted in a 94% reduction in the number Table 3 shows a variety of countermeasures, found in a of risky moves by motorists using the intersection. The review of the literature and through interviews with selected use of four-quadrant gates has continued in Los Angeles transit agencies, which have been tested, implemented, or and they have continued to have success with this counter- suggested to mitigate collisions between LRVs and motor measure. Four-quadrant gates are effective in semi- vehicles at signalized intersections. The sections that follow exclusive rights-of-way, but not for street operations. provide details on each of these countermeasures. Knock-Down Bollards PHYSICAL BARRIERS Coifman and Bertini (3) note that at a typical median LRT Physical barriers provide physical separation between move- crossing with left-turn pocket lanes, the left-turn lanes are ments. Transit agencies have employed a variety of physical often separated from the trackway by a narrow curb, which barriers, including gates, bollards, and delineators to provide may end before the intersection to allow for installation of and physical separation between LRV and motor vehicle move- passage for a pedestrian crosswalk. With the end of this curb ments. These countermeasures are discussed here. at the crosswalk, motorists frequently enter the LRV dynamic envelope during their left turns. The problem is compounded when drivers cross the stop bar and stop at the near side of the Gates crosswalk. In these situations, knock-down bollards can pro- vide a safe and effective means for restricting automobile An FTA-sponsored study was undertaken in 2002 to investi- movements in the crosswalk, effectively reducing the length of gate the use of railroad crossing gates to reduce collisions the potential LRVmotor vehicle collision zone. between LRVs and motor vehicles at intersections where streets run parallel to LRT and motorists are permitted to make left turns across the tracks (8). The two types of gates included Raised Medians or Delineators in the study were: In side-running, semi-exclusive alignments, raised medians or · Left-turn gates, which can be used to physically prohibit delineators can be installed to deter left-turn motorists from motorists from turning left in conflict with an LRV. Left- driving around lowered automatic gates during their turns. In turn gates can be installed parallel to the tracks (along the this application, the raised medians or delineators are installed line separating the left-turn lane from the tracks in a on the cross street, perpendicular to the tracks, between the median-running environment) or at 90 degrees to the left- trackway and the intersection.
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12 TABLE 3 COUNTERMEASURES USED BY TRANSIT AGENCIES TO MITIGATE COLLISIONS BETWEEN LRVS AND MOTOR VEHICLES AT SIGNALIZED INTERSECTIONS Category Countermeasure1 Agency Example(s)2 Physical Barriers Gates (left-turn gates, four-quadrant gates) Calgary Transit, LACMTA Knock-down bollards DART Raised medians/delineators TriMet, DART, NFTA (Buffalo) Retractable delineators/barriers Michigan DOT Traffic Signs Active train-approaching warning signs TriMet, DART, LACMTA Active turn-prohibition signs Houston METRO, TriMet Overhead lane-use control signs LACMTA Use and placement of static signs Sacramento RT, TriMet 2nd train coming warning sign Maryland MTA Signal Displays Red left-turn arrows Denver RTD, TriMet Green arrow aspects for through traffic New Jersey Transit, TriMet In-roadway lights Houston METRO Programmable visibility signal heads TriMet LRT signals with format and color different from traffic LACTMTA, Santa Clara signals VTA Far-side LRV signals TriMet Traffic Signal All-red traffic signal phase LACMTA Phasing Lagging left turns LACMTA, TriMet LRV ìq ueue jump" or "head start" Utah Signal pre-emption phasing TriMet Pavement Contrasting pavement treatments Houston METRO Markings/Treatments Crosshatch pavement markings New Jersey Transit Lane-use markings (arrows) San Francisco MUNI Extending/repositioning pavement treatments/markings Denver RTD Public Public outreach materials LACMTA, Denver RTD Outreach/Education State driver's license handbooks California Enforcement Police presence LACMTA, Houston METRO Photo enforcement LACMTA Other Lower train speeds TriMet Sacramento RT, Houston Train-mounted cameras METRO New Jersey Transit, San LRV operator defensive driving Diego Metropolitan Transit System 1 These countermeasures may not be applicable in all situations, such as emergency or reverse-running operations. 2 The agencies noted are just a few examples of those using the countermeasures. Therefore, the use of the countermeasures is not necessarily limited to the agencies listed here. Retractable Delineators or Barriers available at that time could not be used for the left-turn barrier application as they would not be able to perform the number of Retractable delineators can be installed to block unwanted daily "up and down" cycles required (more than 200/day) at vehicular movements in a number of applications and could be the crossing (8). particularly useful where there is insufficient space for the installation of gates. The Los Angeles Department of Trans- Several other agencies have explored retractable delin- portation (DOT) has investigated the use of retractable delin- eators or barriers since that time. METRO in Houston is eators to block traffic making left turns across the Long Beach currently testing another type of retractable delineator for Blue Line tracks at certain signalized intersections. Discus- use in keeping motorists out of the shared LRVleft-turn sions between the Los Angeles DOT and a supplier in the early lane when trains are approaching. The Michigan DOT, 2000s concluded that the particular retractable delineators FRA, and Norfolk Southern Railway, in cooperation with