Traffic Management Training Via Dedicated Software

Rationale.

Accidentology has been introduced to Masters’ students as a technical discipline which, via

scientific methods, assists specialists to investigate traffic accidents and subsequent body injuries while

considering all circumstances and influences, in order to develop both effective and applicable solutions to

reduce the number of accidents and diminish their severity (Gaiginschi et al., 2006). In compliance with

the recently released EU traffic surveys, we seek to rise our students’ awareness and instruct them with

regard to one of the most alarming issues reported by road safety statistics, i.e. a significant increase in the

number of deaths among vulnerable users such as pedestrians and motorcyclists - despite a global reduction

in the number of fatal road accidents. Within our previous projects, we sought to familiarise our students

with most recent outcomes applied to decease accidents involving vulnerable road users, i.e. pedestrians or

cyclists. Hence, Serre et al. (2006) provides some in-depth accident investigations, numerical simulations

with multibody models and experimental reconstitution with PMHS subjects, in order to identify the

correlation between the velocity of the vehicle and the position of the victim position at the impact moment.

Han et al. (2001) put forward a method to express the relation between the speed, the distance travelled and

the time measured from the impact moment to the final position of the vehicle and the pedestrian.

Statistical data.

Current statistical data highlight the need for increased safety measures with regard to vulnerable

road users. At international level, considerable differences have been recorded in terms of death distribution

as related to road users and country (Brandstaetter, 2012). In Romania, almost half (40%) of the reported

deaths were among pedestrians, 20% drivers, 20% passengers, about 7% cyclists, while only 3% of the

registered deaths belong to the category of motorcyclists (Figure 01 ).

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According to some statistical analyses concerning the category of traffic participants involved in

traffic accidents at regional level, Oțăt (2018) reported a considerable frequency rate of road traffic

accidents among drivers within Dolj County. Hence, we raised our students’ awareness that more than

1,100 victims belonging to the category of drivers were recorded annually, over the whole analysed period.

The second position was occupied by the number of the victims registered among pedestrians. Vehicle

passengers belong to the third group of victims registered during one calendar year (figure 02 ).

Preliminary input data for modelling and analysis vehicle – pedestrian impact.

To achieve the virtual modelling of the vehicle, students had to fulfil the following stages:

First, the students were assisted to set up the scenario of the traffic accident in the virtual

environment while observing the traces and the distances identified at the crime scene.

• Next, students had to establish how the traffic accident produces and to identify the collision

phases.

• During the last stage, students were asked to determine the speed of the vehicle at the time of the

impact and the projection distance of the pedestrian.

Computer-assisted road design.

Road 1: length 60 m, band width 3.5 m, 1 band by way, 2 ways of movement; longitudinal marking

consisting of: Line interrupted> Length 1 = 1.3 m, Length 2 = 1.5 m

Road 2: length 15 m, band width 2.5 m, 1 band by way, 2 ways of movement; longitudinal marking

consisting of: a continuous line interrupted at the intersection level

Road 3: length 15 m, band width 2.5 m, 1 band by way, 2 ways of movement; longitudinal marking

consisting of: a continuous line interrupted at the intersection level

Pedestrian crossing: width 4.0 m; length 1 = 0.7 m; length 2 = 0.4 m; distance from pedestrian

crossings to intersection = 3m.

Vehicle input and setting the pre-collision parameters.

On road 3> a blue Škoda Fabia 1.4 TDI runs foreword. Just before reaching the junction, the

imminence of a danger is detected and the vehicle breaks with a deceleration of 6 m/s2, at a speed

of 15 km/h. The vehicle load is of 75 kg - the driver.

On road 1> a green Volvo S40 1.8 runs foreword at a speed of 80 km/h. Before reaching the

junction, the imminence of a danger is detected and the vehicle breaks with a deceleration of 6

m/s2, at a distance of 20 meters from the pedestrian crossing no. 3, on road 1. Vehicle load: driver

75 kg, 2 rear passengers and 100 kg in the trunk.

On pedestrian crossing no. 3 - road 1 (to the right of the junction)> a male pedestrian walks at a

speed of 4.5 km/h in a step right position. The pedestrian is positioned halfway on the pedestrian

crossing (2 m to the left and 2 m to the right).

Road design.

The road design is accomplished by selecting the Road icon in the toolbar. Once entered in the

working screen, students can set the desired dimensions of the road. For our project, they were asked to

consider three sections of the roadway and observe the dimensions required as input data (figure 02 a).

Road markings set up.

The design of the road markings is completed by selecting the Create polyline polygon icon, once

this option is enabled, students can move a step forward in the working screen, which is positioned over

the road to reproduce the longitudinal markings (figure 02 b).

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Dimensioning of the infrastructure elements.

To set the dimensions of the infrastructure elements, the students are asked to select the Create line

dimension option in the Toolbar, observing the following distances (figure 03 ):

Road section 1 with a length of 35 m up to the intersection and

A pre-set distance of 20 m until the pedestrian crossing no. 3

The determination of the pedestrian crossing no. 3 middle point, respectively 2 m to the left and 2 m to the right.

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Traffic signs input.

The traffic signs are predefined in the platform library. In order to access and input them in the

traffic scenario, students are asked to enter the Image Gallery at the point e - signs, which are classified

according to the category of the traffic signs (figure 04 ). To input a certain traffic sign into the work screen,

students will select and hold the left mouse button (drag and drop).

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Setting the pre-collision data for the traffic participants.

The Virtual Crash software provides the users with a wide library of vehicle models and categories.

To input the traffic participants, students are asked to enter the Vehicle main menu. First they will select

the vehicle category needed for the simulation; the categories provided by the software encompass the

following: buses, vehicles, motorcycles, multi-bodies (pedestrians), trailers and trucks. After setting the

traffic participants into the traffic scenario, the students are assisted to set the pre-collision data for both

vehicles and the pedestrians. From the Edit main menu (figure 05 ), they are required to select the vehicle

whose data will be changed, and at the bottom of the edit menu, the window with the parameters to be input

opens: initial speed, vehicle dynamic state, acceleration value, turning angle. Also, from the Edit menu, the

students can change the geometric data, the load in the vehicle and its colour.

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The students are taught how to set the geometric features, such as mass and height, for each

pedestrian model (figure 06 ). This stage is accomplished by means of the Edit option, selecting the pattern

to be modified, and selecting the Date option. For the right foot position of the pedestrian they enter the

Image Gallery - d - Poses, having identified the position, it overlaps the pedestrian that was previously

placed in the main window.

Determining the speed of the vehicle at the impact moment with the pedestrian.

To determine the vehicle’s speed when impacting the pedestrian, the Virtual Crash platform provides

users with various possibilities. The vehicle speed can be determined by means of the graphical method, by

sequentially navigating the crash phases while moving the mouse pointer over the time bar until the moment

when the first contact between the vehicle and the pedestrian occurs. Once the vehicle is selected, the

software will automatically generate a window with the vehicle parameters. As indicated in figure 07 , the

vehicle speed at the moment of impact with the pedestrian was 58.29 km/h. The second method to determine

the vehicle’s speed is by generating the speed chart over time. Once the phase of the first impact between

the vehicle and the pedestrian has been identified, the speed of the vehicle can be identified on the generated

diagram, i.e. approx. 58 km/h – figure 08 . In the Virtual Crash environment, the pedestrian is designed as

a multi-body. In order to generate a clearer and accessible chart, students are asked to take into consideration

only the speed in the dummy head area, see figure 08 .

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The projection distance of the pedestrian following the impact.

As in the case of speed, students can resort to two variants in order to determine the pedestrian

projection distance. First, within the simulation, by selecting the dimension line option, the students can

establish the distance between the place where the first contact between the vehicle and the pedestrian

occurred and the final position, where the pedestrian was found. Appling this method, the students obtained

a pedestrian projection distance of about 22.5 m, see Figure 09 .

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By generating the speed variation diagram according to the distance travelled, the software allowed

the students to determine the pedestrian projection distance. Figure 10 indicates that the pedestrian has

travelled 3 m at a constant speed until reached to the place where the accident occurred. The total space

that pedestrian travelled before and after the impact is 25.5 m. The pedestrian projection distance is obtained

by decreasing the space before the impact from the total travelled space, i.e. a distance of 22.5 m.

Subsequently, the students grew aware that the results obtained following the application of the two

methods were similar for both vehicle speed and pedestrian projection distance.

Identifying the collision phases.

Moment of impact: The first phase of the impact between the vehicle and the pedestrian is the first

contact between the traffic participants and the cause of the primary lesions suffered by the pedestrian

in the lower limbs - figure 11 .

Taking over and lifting the pedestrian: involves the taking over and lifting of the pedestrian on the

vehicle’s hood to the windscreen. Lifting the pedestrian on the road continues until the lower limbs

are lifted above the torso. The maximum point to which an adult pedestrian is lifted is located at the

boundary between the windscreen and the roof of the vehicle - figure 12 .

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The flight phase: the pedestrian detaches from the contact with the vehicle and is projected forward -

figure 13 .

The projection of the pedestrian on the road: following the pedestrian flight phase on the vehicle’s hood,

the pedestrian is projected on the road.

The final pedestrian position: after being projected on the road, due to inertia, the pedestrian is subjected

to rotation movements on the road until it reaches the final position - figure 14 .

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