Based on a recent decision by the Supreme Court on 2 Ob 48/19a, this article presents the legal aspects of changing lanes using the zipper system.

In the case in question, damage occurred due to a traffic accident because a road user in a convoy wanted to move into the adjacent lane according to the zipper system, but was prevented from doing so by another road user.

A very large number of road users are of the opinion that they have priority on the continuing lane if several lanes merge and other road users want to move into the continuing lane. However, this is not correct, as can be seen in the following explanations.

About the zipper system

There is a provision in the Austrian Road Traffic Regulations (StVO), namely § 11 Para. 5 StVO, which regulates the zipper system. According to this standard, vehicles must be allowed to change to the remaining lane (alternately!) if it is not possible/permissible to drive continuously in one lane on roads with more than one lane(zipper system).

This means that road users are indeed obliged to allow other vehicles in the lane at the end of the lane to move into the continuing lane. The lane change must take place alternately.

This zipper system is used not only when a lane is shifted (due to an obstacle), but also when two lanes are (gradually) narrowed to one. However, the applicability of the zipper system presupposes column traffic, whereby two vehicles are sufficient.

To change lanes

As knowledgeable road users now know, vehicles in an ending lane must be allowed to move into the continuing lane. However, it should of course be noted that a lane change should only be carried out if this is possible without endangering other vehicles. An example of this is when a driver moves into another lane but collides with another road user because he has not made sure that he can change lanes without any problems.

There is therefore a further provision in the Road Traffic Regulations, § 11 Para. 1 StVO, which states that the driver of a vehicle may only change lanes after he has satisfied himself that this is possible without endangering or obstructing other road users.

A lane change must therefore be avoided if there is a mere possibility of endangering or obstructing other road users. Such an obstruction already exists if a following vehicle is forced to brake or swerve.

In particular, a driver must make sure that the person driving in the continuous lane allows him to move into the lane. If the latter is not the case, the driver may not change lanes.

On the decision 2 Ob 48/19a

In particular, this decision stated that If several lanes are available for one direction of travel, but one lane cannot be used any further, the driver concerned must be allowed by the other road users to change lanes using the zipper system in accordance with Section 11 (5) StVO.

However, this regulation does not release the driver from the obligation under Section 11 (1) StVO to ensure that no one is endangered or obstructed before changing lanes. Therefore, the lane may not be changed if it is apparent that the road user following in the other lane will not allow the lane to be changed.

In the case in question, fault was apportioned. The court ruled that the truck driver who, as a result of gross inattention, did not allow a car driver to move into his lane after the zipper system in violation of Section 11 (5) StVO, was more at fault. The driver of the car was accused of misjudging the possibility of changing lanes when looking in the rear-view mirror and thus violating Section 11 (1) StVO.

_Sources:

_{Pürstl, StVO13 (2011) § 11}

_{Kolmasch, Changing lanes according to the zipper system, Zak 2019/610}

_{Supreme Court 25.07.2019, 2 Ob 48/19a}