2.9.

‘Bonnet top’ is the area which is bounded by (a), (b) and (c) as follows: (a) the bonnet leading edge reference line, as defined in point 2.9.2; (b) the bonnet side reference lines as defined in point 2.9.4; (c) the bonnet rear reference line as defined in point 2.9.7. 2.9.1. ‘Bonnet leading edge’ is the front upper outer structure including the bonnet and wings, the upper and side members of the headlight surround and any other attachments. The reference line identifying the position of the leading edge is defined by its height above the ground and by the horizontal distance separating it from the bumper (bumper lead), determined in accordance with points 2.6, 2.9.2 and 2.9.3. 2.9.2. ‘Bonnet leading edge reference line’ is defined as the geometric trace of the points of contact between a straight edge 1 000 mm long and the front surface of the bonnet, when the straight edge, held parallel to the vertical longitudinal plane of the car and inclined rearwards by 50° and with the lower end 600 mm above the ground, is traversed across and in contact with the bonnet leading edge (See Figure 4). For vehicles having the bonnet top surface inclined at essentially 50°, so that the straight edge makes a continuous contact or multiple contacts rather than a point contact, determine the reference line with the straight edge inclined rearwards at an angle of 40°. For vehicles of such shape that the bottom end of the straight edge makes first contact then that contact is taken to be the bonnet leading edge reference line, at that lateral position. For vehicles of such shape that the top end of the straight edge makes first contact then the geometric trace of 1 000 mm wrap around distance as defined in point 2.8, will be used as bonnet leading edge reference line at that lateral position. The top edge of the bumper shall also be regarded as the bonnet leading edge for this Commitment, if it is contacted by the straight edge during this procedure. 2.9.3. ‘Bonnet leading edge height’ for any section of a car is the vertical distance between the ground and the bonnet leading edge reference line defined in point 2.9.2, with the vehicle positioned in its normal ride attitude. 2.9.4. ‘Bonnet side reference line’ is defined as the geometric trace of the highest points of contact between a straight edge 700 mm long and the side of a bonnet, when the straight edge, held parallel to the lateral vertical plane of the car and inclined inwards by 45° is traversed down the side of the Frontal Upper Surface, while maintaining contact with the surface of the body shell (see Figure 5). 2.9.5. ‘Corner reference point’ is the intersection of the bonnet leading edge reference line and of the bonnet side reference line (see Figure 6). 2.9.6. ‘Third of the bonnet leading edge’ is defined as the geometric trace between the ‘Corner reference points’ as defined in point 2.9.5, measured with a flexible tape following the outer contour of the leading edge, divided in three equal parts. 2.9.7. ‘Bonnet rear reference line’ is defined as the geometric trace of the most rearward points of contact between a sphere and the Frontal Upper Surface, as defined in point 2.7, when the sphere is traversed across the Frontal Upper Surface, while maintaining contact with the windscreen (see Figure 7). The wiper blades and arms are removed during this process. For the tests described in Section 3.1 of Annex I to the Directive, the diameter of the sphere is 165 mm. For the tests described in Section 3.2 of Annex I to the Directive, the diameter of the sphere is 165 mm if the lower windscreen frame on the vehicle's centre line is located at a wrap around distance, as defined in point 2.8, of 1 500 mm or more from the ground and the diameter of the sphere is 130 mm when this wrap around distance is less than 1 500 mm. If the bonnet rear reference line is located at a wrap around distance of more than 2 100 mm from the ground, the bonnet rear reference line is defined by the geometric trace of the 2 100 mm wrap around distances, as defined in point 2.8. Where the Bonnet Rear Reference Line and bonnet side reference Lines do not intersect, the Bonnet Rear Reference Line is modified according to the procedure outlined in point 2.9.9. 2.9.8. ‘Third of the bonnet top’ is defined as the geometric trace between the ‘Bonnet side reference lines’ as defined in point 2.9.4, measured with a flexible tape following the outer contour of the bonnet top, divided in three equal parts. 2.9.9. ‘Intersection bonnet rear reference line and bonnet side reference line’ where the bonnet rear reference line and bonnet side reference line do not intersect, the bonnet rear reference line should be extended and/or modified using a semi-circular template, of radius 100 mm. The template should be made of a thin flexible sheet material that easily bends to a single curvature in any direction. The template should, preferably, resist double or complex curvature where this could result in wrinkling. The recommended material is a foam backed thin plastic sheet to allow the template to ‘grip’ the surface of the vehicle. The template should be marked up with four points ‘A’ through ‘D’, as shown in Figure 8, while the template is on a flat surface. The template should be placed on the vehicle with Corners ‘A’ and ‘B’ coincident with the side reference line. Ensuring these two corners remain coincident with the side reference line, the template should be slid progressively rearwards until the arc of the template makes first contact with the bonnet rear reference line. Throughout the process, the template should be curved to follow, as closely as possible, the outer contour of the vehicle's bonnet op, without wrinkling or folding of the template. If the contact between the template and bonnet rear reference line is tangential and the point of tangency lies outside the arc scribed by points ‘C’ and ‘D’, then the bonnet rear reference line is extended and/or modified to follow the circumferential arc of the template to meet the bonnet side reference line, as shown in Figure 9. If the template cannot make simultaneous contact with the bonnet side reference line at points ‘A’ and ‘B’ and tangentially with the bonnet rear reference line, or the point at which the bonnet rear reference line and template touch lies within the arc scribed by points ‘C’ and ‘D’, then additional templates should be used where the radii are increased progressively in increments of 20 mm, until all the above criteria are met. Once defined, the modified bonnet rear reference line is assumed in all subsequent paragraphs and the original ends of the line are no longer used.