Project information from Autobahn GmbH:

The construction of the new wildlife bridge over the A3 motorway aims to reconnect important habitats of native wildlife that have previously been fragmented by the A3. In addition, to protect the wildcat population documented in the planning area, a wildcat protection fence will be erected on both sides of the A3 and integrated into the planned "crossing concept". The Welschehahn parking area, located approximately 600 meters south of the wildlife overpass on the A3 motorway in the direction of Frankfurt, has already been equipped with a wildcat protection fence to separate it from the forest behind it. The construction of the new wildlife overpass is planned as a compensatory measure for construction projects on the A3 and the resulting impact on nature and the landscape, within the framework of the federal "Reconnection" program. It is being implemented, among other things, as part of the recent reorganization and expansion of the traffic areas of the Welschehahn parking area. The construction project includes the construction of a new bridge structure, a wildlife deterrent barrier on the bridge, planting vegetation on the superstructure, and adapting the drainage systems in the area of the bridge structure. Assuming suitable weather conditions and a construction schedule that proceeds as planned, the bridge structure is expected to be completed and opened to traffic by the end of 2029. As part of the construction project, the A3 motorway will initially be widened by 1.50 meters on each side of the outer lanes within the construction zone to accommodate traffic flow during construction, depending on the progress of the work. During the construction, traffic flow will be managed with three narrowed lanes in each direction (Cologne and Frankfurt) that will be diverted around the construction site, while maintaining as many traffic connections as possible. In certain construction phases, temporary full closures of the respective carriageway will be necessary to carry out work such as the bridge lifting. These closures will be implemented during off-peak hours on weekends to minimize traffic disruptions. As part of our press and public relations work, we will provide separate updates on this matter.

The A3 motorway is a heavily trafficked route in the area of the planned green bridge between the Dierdorf and Ransbach-Baumbach interchanges:
The average daily traffic volume (ADT) in the aforementioned section is approximately 86,013 vehicles (vehicles/24h), of which 17.4 percent are heavy goods vehicles.
*The ADT figures are from 2022.

Regarding the structure:

The bridge structure is a 52.7-meter-long and 54.6-meter-wide integral prestressed concrete bridge spanning the A3 motorway. The structure consists of two bridge spans resting on two abutments and a central pier. To prevent a tunnel-like effect for road traffic passing under the very wide (54.6-meter) bridge, the central pier is composed of seven V-shaped steel supports. The bridge spans 50 meters between the approximately 2-meter-high, opaque, and noise-absorbing noise barriers. The total area of the green bridge is around 5,300 square meters. The noise barrier extends to the edge of the embankment and continues for another 20 meters parallel to the highway until it connects to the planned wildcat protection fence. Ecological environmental monitoring is being conducted concurrently with the project. The bridge surface is divided into different zones to provide suitable habitats for each animal. In addition to the grassy maintenance strip, there is an area with shrubs and a woodland strip with dense shrubs and trees that offer hiding places for larger mammals. The sunny side of the green bridge comprises open meadows and herbs for insects, lizards, and birds (woodland clearing). Another grassy maintenance strip adjoins this. A woodland-like habitat will be created on the green bridge. This will be achieved by planting native, site-appropriate trees and shrubs such as rowan, hornbeam, elderberry, blackthorn, or hawthorn. Fallen deadwood provides shelter for small mammals, amphibians, and reptiles. In addition, forest soil will be applied to the bridge so that site-adapted plant communities can develop from the seed potential already present in the soil. Planting is expected to begin in autumn 2029, depending on the construction progress. This will be followed by a one-year completion maintenance period and then at least two years of ongoing development maintenance. Construction schedule (as of August 2026): According to the current planning status, the construction of the entire project is divided into six construction phases. We will provide timely and separate information about the scope and start of each construction phase as part of our press and public relations work. Construction phases 1 and 2 (BA 1 and BA 2) Construction traffic management, including the median crossovers, will be implemented in summer 2026. Traffic will be guided past the construction site on three narrowed lanes in each direction (Cologne and Frankfurt).

During construction phases BA1 and BA2, the two abutments of the green bridge will be built between summer 2026 and approximately the end of 2027. The construction access road will also be built.

Construction Phase 3 (BA 3)

During the third construction phase, the central support pier of the bridge structure is expected to be built in the first half of 2028.

Traffic will be guided past the construction site on both the Frankfurt and Cologne directions, with three narrowed lanes in each direction.

Construction Phase 4 (BA 4)

After completion of the two abutments and the central support pier, the precast concrete elements will be lifted into place in the two bridge spans during the fourth construction phase, expected to begin in summer 2028. To lift the precast concrete elements into the respective bridge span, the carriageway in that span must be temporarily closed. To minimize traffic disruption, this work will be carried out on weekends.

Construction Phases 5 and 6 (BA 5 and BA 6)

In construction phases BA 5 and BA 6, final concrete work will be carried out on the bridge structure. Corrosion protection will also be applied to the central pier. Furthermore, the two abutments will be backfilled, and the bridge parapets and noise barriers will be installed.