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8 geometry; traffic signal timing and pre-emption of the left-turn TYPES OF COLLISIONS OCCURRING BETWEEN phase; and driver factors such as expectancy, confusion, and LIGHT RAIL VEHICLES AND MOTOR VEHICLES AT SIGNALIZED INTERSECTIONS risk-taking (1). These issues could play a role in the occurrence of LRVmotor vehicle collisions. Although these issues were Collision types and circumstances tend to vary between identified in the research conducted more than 12 years ago, agencies, depending on a variety of factors including the envi- most of these issues are challenges that many transit agencies ronment, the initial incorporation of LRT into the city streets, still experience today. driver types and attitudes, and traffic control. Consequently, accident type prevalence differs among transit agencies. ROLE OF THE MOTORIST IN LIGHT RAIL However, transit agencies with LRT systems consistently VEHICLEMOTOR VEHICLE COLLISIONS report that most collisions between LRVs and motor vehicles are caused by motorists making illegal or improper turns or Transit agencies with LRT systems consistently report that running red lights. most collisions between LRVs and motor vehicles are caused by motorists making illegal or improper turns or running red lights. Although there have been special considerations given Left-Turn Collisions to safety in the design and operation of LRT systems, motorists continue to exhibit risky behavior and ignore traffic control Motor vehicles that make illegal turns in front of approach- devices at LRT crossings. ing LRVs account for the greatest percentage of total colli- sions for most LRT systems (5). Data from 1998 show that In a working paper developed for California Partners for motorists making improper left turns in front of light rail Advanced Transit and Highways (PATH) (3), the authors trains caused 62 accidents, 47% of all LRVmotor vehicle reported that one of four critical events on the part of the accidents. This accident occurrence pattern is not specific to motorist must occur before a left-turn collision with an LRV at intersections with LRT, but is consistent with motor vehicle a median-running crossing. These critical events include: accident experience at intersections in general. The Califor- nia Public Utilities Commission found that the second most Disobedience--An inappropriately low perception of common cause of LRVmotor vehicle accidents was the risk and expectations from conventional intersections problem of motor vehicles running red lights or driving around contribute to driver disobedience. For example, motorists gates (6). may violate static "No Turn on Red" signs at conven- tional intersections with little to no consequences; how- In a traffic safety assessment that took place 1 month after ever, when the perception of risk and expectation from Houston's METRORail began operation, researchers stated this situation at a conventional intersection is transferred that the most common type of collision between motor vehi- to an intersection with LRT, the same action can have cles and METRORail vehicles involved illegal left-hand more serious consequences. turns by motorists. Despite traffic signs and signals designed Failure to perceive--This occurs when motorists do to control the location and timing of left-turn movements not observe the traffic control devices. For example, a along the rail line, several motorists turned into or in front of motorist who sees the adjacent through-traffic's signal oncoming LRVs, sometimes turning from an incorrect lane. turn green and the through vehicles proceed into the All collisions examined appeared to have been the result of intersection may not perceive that the left-turn signal is improper or illegal turns or other driver errors. Illegal left red owing to an approaching LRV. turns are a primary source of motoristLRV collisions in other Misinterpretation--Misinterpretation accidents are light rail systems as well (5). related to expectation errors and cognitive limitations of motorists, and they can be more likely to occur at complicated intersections such as those that incorpo- Right-Angle Collisions rate LRT. Violation of drivers' expectations--When driver expec- A paper presented at the 2006 APTA Rail Conference dis- tancy is violated, it can lead to accidents. Drivers grow cusses stop bar violations on the cross-street approaches to accustomed to intersections operating in a certain way, intersections with LRT crossings (7). It describes the special which may lead them to anticipate movements. For considerations given to safety in the design and operation example, in an area where leading left turns are used pre- of the LRT system; however, motorists continue to exhibit dominately, a collision between an LRV and a motorist risky behavior and ignore traffic control devices at LRT turning left could occur if the motorist proceeds into roadway crossings. Risky behavior includes the failure of the intersection in anticipation of the leading left-turn motorists to acknowledge traffic signals, to obey active phase only to discover that it has been pre-empted by an warning devices, and to stop within clear zones--all of approaching LRV. In other words, drivers' expectations which can lead to right-angle collisions between LRVs and affect driver behavior. motor vehicles.