AFRY als Generalplaner des Kaiserleikreisels

Urban mobility transformation in Germany: Kaiserlei Roundabout

Europe's formerly largest roundabout: The Kaiserlei roundabout in Offenbach

With a diameter of around 190 metres, the Kaiserlei roundabout was once Europe’s largest. Handling about 70,000 vehicles daily, it had reached its capacity limit and become a frequent accident site. AFRY acted as general planner, helping redesign the junction for safer and more efficient traffic.

The reconstruction improves traffic efficiency by separating interregional motorway traffic from local traffic. The redesigned road system is built to accommodate up to 94,000 vehicles per day in the future.

A new district is being developed

For this purpose, intelligent traffic light systems are used at all intersections, which control traffic according to volume and, if necessary, prioritize traffic flows such as motorway exits in case of congestion.

The urban development of the new Kaiserlei district should also be promoted through the development of new commercial areas.

Directly adjacent to the Kaiserlei interchange, the new Kaiserlei district is planned to be built on an area of approximately 40 hectares, providing space and infrastructure for around 3,000 residents and 10,000 employees. As part of the urban development project for the new Kaiserlei district, jointly pursued by both cities, the redesign of the existing interchange has been completed.

The reconstruction of the Kaiserlei roundabout in rough figures:

40,900 m² of road surface
11,220 m² of walkways
5,660 m² of cycle paths
Two five-span prestressed concrete bridge structures, each over 125m long
7,300m³ (approx. 18,000 tons) of concrete were used in the construction of the bridges.
Bridge foundation using approximately 3,500 linear meters of bored piles (1.20m diameter)
Construction of approximately 317 linear meters of retaining walls (up to 5.75 m high),
13 traffic junctions regulated by traffic lights,
18,600 m² of green space with 183 trees,
Over 4,000 m of drainage and connection pipes
Approximately 70,000 meters of various utility lines were laid.

Five-year construction period

The decision to improve the efficiency of this transport hub, an important link between Offenbach and Frankfurt and a feeder road to Frankfurt Airport, was followed by a construction period of over five years. This was officially completed in mid-December 2022.

A major challenge also lay underground. A total of approximately 70,000 meters of utility lines – from telecommunications, data lines, water pipes and low voltage to 110kV high voltage – were laid, thus making the area digitally future-proof.

As part of the reconstruction, connections for cyclists and pedestrians were significantly improved, and the traffic patterns were separated and streamlined. This has made both cycling and pedestrian traffic considerably safer.

Renewal during ongoing operations

The entire reconstruction of the Kaiserlei area was carried out while traffic continued to flow. A well-planned traffic and construction phase concept made this possible.

It is worth mentioning that the accident rate across the entire project area was significantly reduced even during the construction phase.

In addition to the main works on the interchange and the road traffic facilities, public transport was also significantly improved.

Paving the way for a transport revolution

In addition to making all bus stops accessible, an additional bus turning facility was also built, which significantly strengthens public transport in Offenbach.

During the renovation process, new buses with electric drives were purchased from the Offenbach transport company (OVB) and the bus turning facility was quickly equipped with 4 charging points.

In conjunction with the public hydrogen filling station already built in advance, which was also planned and supervised by AFRY, on the grounds of the Hyundai Germany headquarters, the foundations for the mobility transition have already been successfully implemented at Kaiserlei.