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A summarized review of the literature on different pedestrian safety countermeasures is presented in this chapter. It focuses primarily on documentation related to the various and their effectiveness.
Van Houten and Malenfant (1992) evaluated the effectiveness of signs reading “STOP HERE FOR PEDESTRIANS” alone 50 feet upstream of crosswalk and in conjunction with advance stop lines at multilane crosswalks with pedestrian activated amber flashing lights [1]. The type of motor vehicle conflicts, distance the motorists stopped upstream of the crosswalk when yielding to pedestrians, and the percentage of motorists yielding to pedestrians are determined from field observations. Results indicated that signs alone increased the distance that motorists stopped upstream of the crosswalk when yielding to pedestrians and also decreased the percentage of motor vehicle-pedestrian conflicts. The addition of advance stop lines produced a further increase in the distance that motorists stopped upstream of the crosswalk and further reductions in the percentage of motor-vehicle conflicts. These results are observed under conditions when pedestrians activated and did not activate the amber flashing crosswalk light. It is also observed that the percentage of pedestrians activating the light seemed to be a function of the amount of traffic on the street.
Van Houten, Malenfant and McCusker (2001) studied two problems; the difference between the ‘yield’ and ‘stop’ situation while using the advance stop lines, and the use of text rather than symbol sign to support the markings [2]. The advance yield markings and signs are placed at different distances in advance of the crosswalks to determine their effectiveness. Motorist and pedestrian behaviors measured included the occurrence of motor vehicle/pedestrian conflicts such as evasive action, the distance motorists stopped before the crosswalk when yielding to pedestrians, and the percentage of motorists yielding to pedestrians. It is found that placing the advance yield markings and signs as close as 10 m upstream the crosswalk and as far back as 15 m or even 25 m in advance of the crosswalk is effective. Although not all vehicles stopped at or near the yield lines, many motorists stopped 9 m or more upstream the crosswalk. It is noted that motorists tended to stop closer to the crosswalk during the treatment condition when traffic is heavy and vehicles are traveling slowly. Much of the improved yielding is likely the result of improved visibility of pedestrians crossing in front of vehicles stopped in advance of the crosswalk.
Van Houten (1998) studied the effect of specific signs and stop line bars designed to influence motorists to stop further upstream from the crosswalk when yielding right of way to pedestrians [3]. Results indicated that such a simple, inexpensive prompting intervention could reduce conflicts between motorists and pedestrians. The introduction of the prompt and stop line reduced motor-vehicle-pedestrian conflicts by almost 80%.
Abdulsattar, Tarawneh, McCoy, and Kachman (1996) evaluated the effectiveness of the “turning traffic must yield to pedestrians” sign. Such signs are installed at 12 marked crosswalks and data are collected before and after the installation of the signs. The measure of effectiveness considered is vehicle-pedestrian conflicts. The results showed that the sign is effective in reducing left-turn conflicts by 20 to 65 percent, and right-turn conflicts by 15 to 30 percent. Both reductions are statistically significant at the 0.05 level [4].
Abdulsattar and McCoy (1999) conducted drivers’ comprehension of a “turning traffic must yield to pedestrians” sign among different age groups during turning maneuvers. For the left-turn situation, younger drivers (under 56 years) paid more attention to the sign than older drivers. During right-turn movements, drivers and pedestrians always are in interaction, unless exclusive right-turn phase is provided. However, this research lacks info on other measures of effectiveness such as motorists’ yielding behaviors, pedestrian and vehicle delay, and vehicle speed [5].
Huybers, Van Houten and Malenfant (2004) studied the effects of a symbolic ‘‘yield here to pedestrians’’ sign and advance yield pavement markings on pedestrian/motor vehicle conflicts, motorists’ yielding behavior, and the distance motorists’ yield in advance of crosswalks at multilane crosswalks at uncontrolled T intersections [6]. When the sign symbolic is used alone, there is a reduction in pedestrian/motor vehicle conflicts and increased motorist yielding distance. The use of fluorescent yellow-green sheeting as the background of the sign did not increase the effectiveness of the sign. Further reductions in pedestrian/motor vehicle conflicts and further increases in yielding distance are associated with the addition of advance yield pavement markings. Advance yield pavement markings, when used alone, are as effective in reducing pedestrian/motor vehicle conflicts and increasing yielding distance as the sign combined with pavement markings.
Retting, Van Houten, Malenfant, Van Houten and Farmer (1996) discussed an experiment in which special signs and pavement markings are used to prompt pedestrians to look for turning vehicles [7]. Three signalized intersections are chosen, two in Nova Scotia, Canada, and one in Clearwater, Florida for the study. All sites are studied before, immediately after, and approximately one year after prompts are introduced. At Nova Scotia, signs which says “Pedestrians: LOOK FOR TURNING VEHICLES” are installed at one site and painted prompts that read “WATCH TURNING VEHICLES” are installed at the second site. After observations are recorded, painted prompts are added to the signs and vice versa. At Clearwater, signs and painted prompts are installed together. The introduction of either sign or painted prompts alone increased the percentage of pedestrians looking for turning vehicles. With the introduction of second prompt, a further improvement in the percentage of pedestrians looking for vehicles is observed. Introduction of both prompts together led to a large increase in the percentage of pedestrians looking for vehicles. It is also noted that the conflicts are nearly eliminated by the prompting interventions.
Van Houten, Malenfant, Van Houten, and Retting (1997) evaluated auditory pedestrian signals and their effect in reducing vehicle and pedestrian conflicts [8]. The percentage of pedestrians not looking for potential threats and conflicts are reduced after the implementation of an auditory signal.
Turner, Fitzpatrick, Brewer and Park (2006) evaluated engineering treatments that can be used to improve the safety of pedestrians crossing in marked crosswalks on busy arterials [9]. They also discussed the analysis of street and traffic characteristics that influenced motorist yielding at un-signalized intersections. The devices that showed red indication to the motorist had a more significant compliance rate than the devices that did not show a red indication. The measured motorist yielding distance for many crossing treatments varied considerably among sites. A statistical analysis did not find any significant differences between many of the crossing treatments even though the difference in average compliance rates appeared to be practically significant. The number of lanes crossed by the pedestrians and the posted speed limit had an effect on the performance of treatments.
Huang, Zegeer, and Nassi (2000) studied a behavioral evaluation of three devices at a eleven locations under different conditions [10]. Pedestrian safety cones in New York and an overhead crosswalk sign in Seattle appeared to be promising tools for enhancing pedestrian safety at mid-block crosswalks on low-speed two-lane roads. The pedestrian-activated signs in Tucson are not as effective in increasing compliance with other devices as they are installed on four and six-lane high speed arterials. None of the treatments had a clear effect on whether people crossed in the crosswalk. The devices by themselves did not ensure that motorists will slow down and yield to pedestrians.
Hakkert, Gitelman, and Ben-Shabat (2002) conducted a study on crosswalk warning systems. Vehicle speeds about 30 m upstream of the crosswalk and near the crosswalk are measured. Drivers’ yielding behavior to pedestrians is considered in three situations: when a pedestrian is on the sidewalk; when a pedestrian is on the road at the beginning of crosswalk on crossing maneuver; and when a pedestrian is in the middle of crosswalk on a crossing maneuver. Pedestrians crossing within 5 to 30 m of crosswalk are counted. Conflict rates of vehicles and pedestrians are reduced significantly to less than 1 percent. A reduction to 10 percent in the proportion of pedestrians crossing outside the crosswalk is observed [11].
Nasar (2003) conducted a study to evaluate the effectiveness of written signs with social assistance to increase the proportion of drivers stopping for pedestrians in crosswalks. The written signs with social assistance are “Thank you for stopping” “Please stop next time.” If the driver stopped, the pedestrian crosser held up a green “Thank you for stopping” signs to drivers. If the driver did not stop, a confederate held up a pink “Please stop next time.” In weeks 1 and 3, baseline data on the proportion of drivers stopping for pedestrians at two sites are obtained. In week 2, the stopping behavior of motorists is observed with social assistance signs. An ABA reversal design is used to evaluate the effectiveness of strategies. The analysis showed a significant increase in stopping behavior of drivers during the treatment condition (50.9 percent) from the baseline conditions (46 percent and 37.3 percent) [12].
Eccles, Tao, and Mangum (2004) evaluated the pedestrian countdown signals in Montgomery County, Maryland [13]. A “Before and after” study technique is used to evaluate motorists’ and pedestrians’ behavior and vehicle speed. The results revealed a significant positive effect on pedestrian behavior and did not have any negative effect on motorist behavior. No effect on vehicle approach speed is observed due to the presence of countdown signals while vehicles entered intersections during clearance intervals [13].
The presence of pedestrian countdown signals caused more pedestrians to enter the crosswalk during the flashing DON’T WALK phase. A larger proportion of pedestrians completed crossing on the flashing DON’T WALK. This, in turn, reduces the chance of more pedestrians completing the crossing maneuver before DON’T WALK [14]. The pre- and post-installation research showed that an addition informational, a numerical descending countdown timer during the flashing DON’T WALK clearance interval, is intuitively understood and used successfully by pedestrians. Pedestrians of over the age of 16 well understood countdown pedestrian indication and used the information appropriately [15].
Van Houten, Retting, Van Houten, Farmer, and Malenfant (1999) evaluated a LED pedestrian signal head with animated eyes that scan from side to side at the start of the WALK indication. The study was conducted at two signalized intersections in downtown Clearwater, Florida, U.S.A. The results demonstrated that the experimental signal decreased the percentage of pedestrians not looking for turning vehicles and vehicle-pedestrian conflicts; similar results were obtained during a follow up study after six months.
Van Houten, Van Houten, Malenfant, and Andrus (1999) conducted a study to evaluate the effectiveness of animated eyes on drivers’ behavior. Observers scored data on whether motorist looked right and left before crossing the sidewalk and vehicle-pedestrian conflict. They found a significant reduction in vehicle-pedestrian conflict and an increase in percentage of pedestrians and motorists cautionary for particular threats.
Van Houten and Malenfant (2001) conducted a study on an ITS animated LED signal designed to alert drivers to the presence of pedestrians crossing in front of them at the exit to an indoor parking garage and a mid-block-crosswalk location. Data are collected on each of 25 drivers per daily session at the parking-garage exit and two sets of 20 pedestrians and at least as many drivers during each daily session of the experiment. The study demonstrated that the introduction of the ITS signs are associated with an increase in the percentage of motorists yielding to pedestrians at both the garage exit and mid-block crosswalk locations, and the eyes produced a significantly larger increase than the flashing beacon at the mid-block crossing. Although conflicts are lower when the ITS signal is in place, the number of conflicts occurring during the baseline condition are not significantly high enough to detect an effect. At the mid-block site, both the ITS signal and the yellow beacon are associated with a reduction in the percentage of pedestrians stranded in the center of the road, and the number of conflicts. The ITS ‘eyes’ display produced a significantly larger increase in the percentage of drivers yielding to pedestrians than the flashing beacon even though both devices only operated when a pedestrian is crossing the street. Specifically, the pedestrian icon showed the direction of the pedestrian who is crossing the street, and the searching ‘eyes’ display provided a specific request of the drivers to look for the pedestrian. Analysis of the data revealed that the ITS eyes display is inherently understood by drivers and produced a significant increase in yielding behavior and a reduction in conflicts [16].
Van Houten, Malenfant, Van Houten and Andrus (1999) evaluated the effectiveness of animated eyes display as a possible countermeasure at an indoor parking garage exit. The analysis of the study indicated an increase in the number of motorists who look for pedestrians in either direction leaving the garage exit. The increase is maintained three months after the animated eyes are introduced. The use of large electronic displays offered several advantages over incandescent light, including low power requirements and low cost. The use of animated EYES displays directed at drivers might prove a helpful tool in reducing the crashes. The study demonstrated that animated eyes also can increase motorist observing behavior [17].
Carsten, Sherborne, and Rothengatter (1998) evaluated innovative pedestrian signalized crossings as a part of DRIVE II project VRU-TOO (Vulnerable Road User Traffic Observation and Optimization). Signals are designed to make timings more responsive to pedestrian needs, i.e., to affect signal timings. As a part of innovative signalized pedestrian crossings, microwave detectors are mounted on traffic signals to register the approach of pedestrians. Microwave detection can be applied to replace the normal push-button on signalized pedestrian crossings, provide an earlier activation of the pedestrian phase, provide an extension of the pedestrian phase for late arrivals, and provide longer pedestrian phases when there are large numbers of pedestrians. These signals are installed in three European countries. The site one is in Leeds, England, and flows are up to 6,000 pedestrians an hour. The other two sites, one in Portugal and the other in Greece, had comparatively lower pedestrian flows. Some of the criteria used for evaluation are pedestrian-to-vehicle conflicts, percentage of pedestrians arriving on red who violated the red light (especially the percentage violating red when motorists had green), pedestrian comfort, and the number of encounters between pedestrians and vehicles (an encounter is defined as an interaction between a pedestrian and a vehicle where one needs to change course or speed due to others behavior). They found that pedestrian-to-vehicle conflicts are reduced in the after studies in most of the sites. However, the reduction in conflict in all of the sites is not statistically significant. At site two in Leeds, conflicts are also analyzed in relation to pedestrian flow. The conflict to flow ratio decreased from 1:2,034 in the before study to 1:2,300 in the after study. There is a reduction in the proportion of pedestrians who experienced long waiting times (>30 seconds). Mean queue length decreased at all three sites in Leeds. However, maximum queue lengths went up at two sites [18].
Retting, Nitzburg, Farmer, and Knoblauch (2002) reported finding from a field evaluation of two methods for restricting right turn on red (RTOR) to promote pedestrian safety. The implementation of signs prohibiting RTOR during specified hours yields better results than signs giving drivers discretion to determine whether pedestrians are present [19].
Van Houten and Malenfant (2001) analyzed the effectiveness of an ITS LED at parking garage exit and mid-block locations. The main purpose of the study was to assess the effectiveness of an ITS signal that included animated eyes and pedestrian symbols at a garage exit with limited visibility. The result of the study showed that the introduction of ITS signs increased the percentage of motorists yielding to pedestrians at the garage exit and mid-block crosswalk location. The ITS eyes sign produced a significantly larger increase in driver’s yielding behavior than a flashing beacon at the mid-block crossing.
Nitzburg and Knoblauch (2001) conducted a study to evaluate high-visibility ladder style crosswalk with illuminated overhead crosswalk sign treatment in low volume and low speed un-signalized intersections in Clearwater, Florida. Traffic volumes, traffic gaps, and drivers’ and pedestrians’ behavior at control sites and experimental sites are observed. Yielding behavior of drivers in daytime at first half, second half, and both halves of crossing are found is statistically better in experimental sites as compared to comparison sites [20].
Huang and Cynecki (2000) evaluated the effectiveness of various traffic calming treatments on pedestrian and motorist behavior at different locations. The treatments included bulb-outs, raised intersection, and Refuge Island. Before and after data are collected and analyzed for their statistical significance. It is found that the raised intersections and refuge islands are likely to direct more pedestrians to cross within the crosswalk. At most other sites, traffic calming devices did not appear to have significant effects on pedestrians. The bulb-outs in Seattle are associated with increased wait times and a lower percentage of those who crossed in the crosswalk, both undesirable effects from a pedestrian standpoint. These devices by themselves neither ensured that motorists will slow down and yield to pedestrians, nor those pedestrians will cross in the crosswalk. Sometimes these treatments hindered the activities such as street cleaning and snowplowing, impeding emergency vehicle access, and might affect drainage. In addition, the noise of vehicles going over speed humps, raised crosswalks, or raised intersections might disturb nearby residents [21].
Lalani (2001) discussed comprehensive information about the effectiveness of various treatments for pedestrian safety. The information is gathered from different sources including experts, internet surveys and references throughout the world. Based on the information reviewed, it is found that marked crosswalks at uncontrolled locations on higher-volume, multilane facilities using traditional treatments leads to higher pedestrian-related collision rates than at unmarked crosswalks on similar facilities. Installing marked crosswalks, especially at uncontrolled locations, by striping two lines across the roadway and posting a single sign in advance of and at the crossing did not improve pedestrian safety. A variety of low-cost signing and striping techniques are currently being used to improve the safety. A number of higher-cost geometric design features, such as curb extensions and pedestrian refuge islands are used to improve the safety of marked crosswalks. Some studies indicated that removing uncontrolled marked crosswalks from higher-volume, multilane facilities at some locations showed reductions in the rate of pedestrian related collisions. It is also suggested that different intelligent transportation systems based techniques could be employed for improving pedestrian safety [22].
The literature includes documents on the effectiveness of crossing refuge islands as relatively inexpensive devices to protect pedestrians. Pedestrian refuges or crossing islands are raised islands in the center of roadways, allowing pedestrians to cross one half of the street, with a safe place to stop before crossing to the other side of the street. They are typically constructed at marked crosswalks, either at a mid-block location or at an intersection. The crossing islands are best employed when traffic volumes result in few gaps for pedestrians to safely cross the entire street at one shot. Also, they can be deployed when there is little demand to make left turns, and the roadway is particularly wide. A series of studies on the effect of traffic calming measures in six German cities concluded that, “the modification of streets has proven to be more effective than reducing the speed limit. The weaker road users children, pedestrians, and cyclists benefited more from the measures [23].”
Pedestrian refuge islands are particularly suitable for wide two-way streets with four or more lanes of moving traffic traveling at higher speeds. They are particularly useful to persons with mobility disabilities, very old or very young pedestrians who walk at slower speeds, and persons who are in wheelchairs. Wheelchair users need adequate width and level areas for waiting on the refuge. Split Pedestrian Cross-Overs or Danish Offsets are laid out in a staggered configuration at uncontrolled or signalized intersections, requiring pedestrians to walk toward traffic to reach the second half of the crosswalk. These are useful at skewed intersections. It enables pedestrians to focus on crossing each direction of traffic separately and provides a “refuge” in the middle of the street. By requiring pedestrians to walk facing oncoming traffic, the refuge provides them a better view of oncoming traffic and allows drivers to clearly see pedestrians. Previous studies on pedestrian refuge islands found significance effect of this countermeasure on motorist and pedestrian behavior [21, 22, 24]. The literatures provide evidence that the drivers are more likely to yield at high-visibility crosswalk, and advance yield marking locations.
Bergman, Gray, Moffat, Simpson, and Rivara (2002) conducted a study on inducing city authorities to apply for state funds for creating a model pedestrian refuge in their communities. Ten demonstration sites are funded; seven of them are built or are under construction. There is no guarantee, however, that the presence of the model refuges would lead to community-wide application of these safety enhancements. First, progress in pedestrian safety occurred in small steps. Limited and realistic goals had to be set. The work group is able to meet all the goals established at the outset of the project. Second, the importance of bringing decision makers into the process early and providing them with regular updates is reinforced. Third, media coverage is critical to raising the awareness of public officials. An emotional link is created between the public and the families of trauma victims. Centering kick-off on the events surrounding the death of a child gave the campaign vital energy. The knowledge and energy mobilized by these individuals are needed to continue working with the local engineering staff as the pedestrian safety measures are designed for construction [24].
Speeding is attributed to thousands of crashes in work zones each year leading to numerous fatalities and injuries. Sizeable portion of these crashes due to excessive speed emphasizes the need to motivate drivers to comply with speed limits especially in work zones. Studies have shown that most drivers do not slow down in response to the standard regulatory or advisory speed signs that are customarily used to regulate speeds at temporary traffic control zones (work zones) [25]. Research conducted to determine effectiveness of speed trailer to motivate and encourage drivers to observe posted speed limits in work zones indicated that devices with the ability to display drivers' speeds have considerable potential for reducing speeds and improving compliance [25-29]. A study in Netherlands showed that local automatic speed warning at an urban intersection reduced the mean speed by 5 km/hr [30]. Also, on a two-lane rural road, the percentage of speeders decreased from 40 to 10 percent. The total number of crashes is reduced by 35 percent. This effect is almost the same three years after concluding the experiment [30]. One case study showed that the efficacy of using radar as a speed reduction strategy is a function of congestion and radar detector density, with the strategy being most effective for volumes levels between 200 and 1,400 vehicles per hour per lane [31]. However, one of the researchers found that speed trailer did not influence the speed of the fastest 15 percent of the speeding vehicles. Also, it did not affect the heavy vehicle speeds [32].
Even though it is observed by some of the investigators that increasing the speed limit reduces the crash rate [33-38], the severity of a pedestrian-related-vehicle-crash dramatically increases with the increase in speed [39, 40]. Newton's laws dictate that a doubling in vehicle speed results in a stopping distance four times as long and four times as much kinetic energy absorbed during an impact. Higher driver response times further increase stopping distances. As a result, a small increase in roadway traffic speeds results in a disproportionately large increase in pedestrian fatalities.
According to the studies conducted by two different agencies, the probability of a pedestrian fatality increases at an alarming rate i.e., from 5 percent to 40 percent when the speed at impact with a pedestrian increases from 20 to 30 mph and to about 85 percent for a speed of 40 mph [41, 42]. These data showed that the likelihood of a pedestrian fatality increases in a nonlinear fashion, much faster than the percentage increase in vehicle speed. Hence, speed control plays an important role in the improving pedestrian safety of a region. Traffic calming uses geometric changes to influence travel speed and to perhaps cause drivers to select another route for travel. It is intended to restore local streets to their intended function, thus providing a more livable environment for residents. In most cases, problems on local streets are caused by through traffic, speeding, and/or noise. Speed management goes a step beyond traffic calming by also looking at higher speed facilities, including collectors and arterials. Many of the typical traffic calming techniques used in residential areas to control volume and speed would be difficult to implement on these roadways. However, other techniques need only modifications or a different approach to be effective. The most frequently used techniques on collectors and arterials are:
Speed or radar trailers are mobile roadside devices that use radar to measure the speed of approaching vehicles and display the speed to passing drivers in an effort to decrease speed [43]. The portable units show the posted speed limit of the roadway and display the current speed of the approaching vehicle. Speed trailers have been used as an enforcement tool in some areas when police officers enforce the speeds. However, they are mainly used as a public relations measure to inform motorists of their speeds with the assumption that the speeding motorists would voluntarily reduce their speed. Speed trailers are also used for automated enforcement in a few states, where speeds and license plate numbers are recorded by hidden cameras and citations are issued by the local law enforcement agency. Equipment to collect traffic volumes may also be used within the speed trailer.
A study conducted by Brown (1992) on concentrated police enforcement had shown to positively influence driver behavior, but is difficult to apply to rural contexts. Signs of police enforcement in high crash-risk areas are placed in two rural locations in South Australia. The effects of these signs on vehicle speed are evaluated by conducting radar surveys of mean speeds on the approaches to, and exits from, the sign locations before and after their erection. A minor speed reduction on the exit from one of the signs is observed, but this is not observed in the speeds of the fastest 15 percent of vehicles. This suggested that the highest risk group of speeders is not affected by the signs. The signs did not affect heavy vehicle speeds. It is not considered likely that the signs had a substantial effect on road safety in rural areas [32].
In the United Kingdom, Puffin (Pedestrian User-Friendly Intelligent) crossings respond to pedestrian demand and do not delay traffic unnecessarily when no pedestrians are present [44]. Pedestrian presence is sensed either by use of a pressure-sensitive mat or by an infrared detector mounted above the crossing location. Pressure on the mat is used both for initial detection as well as to confirm that the pedestrian has not departed the crossing zone before the Walk signal appears. If the pedestrian departs the crossing zone prior to the appearance of the Walk signal, the call will be canceled.
Puffin crossings may also utilize an additional sensor to detect the continued presence of pedestrians in the crosswalk, thereby allowing the signal phase to be extended for those requiring additional time to cross. The conversion of a standard signal to a Puffin crossing in Victoria, Australia, reduced by 10 percent the number of pedestrians who started to cross before the pedestrian Walk signal is presented [45]. Similar results are reported in Växjö, Sweden [46]. The Swedish results also showed that the number of vehicle-pedestrian conflicts decreased after the microwave detectors are in place.
The Dutch PUSSYCATS (Pedestrian Urban Safety System and Comfort At Traffic Signals) system consists of a pressure-sensitive mat to detect pedestrians waiting to cross, infrared sensors to detect pedestrians within the crossing, and a near-side pedestrian display [47]. Although pedestrians perceived PUSSYCATS to be at least as safe as the old system, many pedestrians reported that they did not understand the function of the mat. As many as half of all pedestrians refuse to use the system. Similar applications are being used in the United Kingdom and France [48].
Various research efforts have reported on the evaluation of the pedestrian safety countermeasures. Literature related to countermeasures evaluation includes “smart lighting,” “pedestrian countdown signals,” “portable speed trailers,” “turning traffic must yield to pedestrians signs,” “in-roadway knockdown signs,” “high visibility crosswalks,” “warning signs for motorists,” “regulatory signs for motorists,” and “advance yield markings.” However, the literature review identified a need to improve on systematic evaluation of the countermeasures. Identifying potential MOEs for safety countermeasures and evaluating the effectiveness of key countermeasures in a systematic way is the main focus of this research.
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