As part of the scientific support for the Germany-wide field trial with Long Trucks (LHVs) this part of the investigation incorporates safety effects of overtaking and clearing of LHVs. Due to the fact, that the number of LHVs participating in this field test is relatively small, measurements and observations are only performed from the LHV itself. Another reason for this is the priority use of LHVs on motorways and therefore the missing street sections on country roads. The collected data contains information about the behavior of overtaking vehicles during the overtaking process, including approaching, lane switching, passing and reeving back in front of the LHV. The performed analysis of 200 overtaking maneuvers of LHVs or compared vehicles (this analysis used a truck trailer, because it is shorter than an articulated train and therefore reflects the worst case) offers no evidence for an increased safety risk in overtaking a LHV. Given a situation in which an LHV is being overtaken, the marginal values of safety distances tend to enlarge to a reasonable extent. The accelerations at a critical velocity of the overtaking vehicle are slightly above average. Therefore, this study cannot offer any arguments to support the assumption of a greater safety risk in the clearing of transport hubs by LHVs. All in all, the data confirms that LHVs have a lower velocity than a compared vehicle during an overtaking manoeuver. The greater velocity difference between the overtaking vehicle and the vehicle being overtaken might imply that these overtaking manoeuvers are safer than the convenient ones. However, a systematically lower velocity of LHVs would probably lead mainly on motorways to a higher number of overtaking manoeuvers by other trucks. During the continuous operation of LHVs in future matching velocities can be expected. Even in this case, no evidence was found that a higher safety risk exists: All parameters show that the marginal values of critical overtaking maneuvers rise in accordance to the length of the truck. Theoretically, this indicates that the greater distance at least compensates the superior length of the LHV. Therefore, an increased risk seems rather unlikely. (Author/publisher)
Samenvatting