Cable cars are considered the safest means of transportation in the world. Statistics from government authorities worldwide show that there are far fewer accidents per kilometer travelled than by car, bus or train.

This is also confirmed by the German Association of Technical Inspection Agencies (TÜV e.V.). According to them, cable cars are among the safest means of transportation, as they do not encounter other means of transportation at any point and are intensively monitored and extensively inspected during operation. In addition to an annual inspection by an external, independent inspection body, the operator must also carry out a major interim inspection. These inspections include all components and assemblies as well as checking the entire system for safety and functionality (ropes, brakes, entry, coupling and uncoupling as well as all electrical monitoring equipment, etc.). There are also weekly and monthly inspections of individual ropeway systems and their components.

Safety must already be taken into account in the planning process and during the construction of a new ropeway system. A new EU Ropeway Regulation (EU) 2016/424 has been in force since April 2018 and harmonizes the legal requirements for the market access of ropeways and their subsystems throughout Europe. In Germany, it is implemented by the ropeway laws and ropeway ordinances of the individual federal states; in Bonn, the law on ropeways in North Rhine-Westphalia (SeilbG NRW) applies.

In addition to the technical requirements, the rescue options must also be specified for commissioning. Only after a successful inspection does the responsible cable car authority approve operation.

Compliance with all safety measures for cable cars in Germany is monitored by the federal states. As a general rule, independent inspection bodies inspect the entire installation every year. They examine all cable car systems (electrics, braking systems, cabins and ropes) and identify possible wire breaks or irregularities in the rope. Emergency and evacuation measures are also checked.

The operator of the ropeway must also carry out an interim inspection and submit the results to the responsible supervisory authority. In addition, the operating personnel inspect the technology monthly (e.g. function of the monitoring systems) or weekly (e.g. visual inspection of the hauling ropes). Should an emergency nevertheless occur, both the system operators and height rescue units are trained for these situations and regularly practice evacuation in emergency drills.

First of all: statistically, cable cars are the safest means of transport after airplanes. The planned installation in Bonn can operate up to a speed of 19 meters per second crosswind against the axis, which is 68 kilometers per hour. The more precise wind measurement along the route in the Rhine Valley - exactly at right angles to the direction of travel - will only be carried out in an expert report that will be prepared for further in-depth planning and for the  planning approval procedure.

In the case of cable cars, a measuring device for wind speed and wind direction must be available in the area of the route where the strongest crosswind is to be expected. When the wind blows too strongly to allow a ropeway to continue running is determined individually for each installation. As a general rule, cable cars can run in strong winds, possibly at a slower speed depending on the wind strength and the installation. However, if the anemometers report a wind force above which a "wind alarm" applies for this installation, the operator receives acoustic and visual signals and informs the other operators. The cable car then continues to hover slowly until all passengers can get off at the next station. Operation is stopped and the empty cabins remain in the air. Only if extreme conditions are expected that endanger the entire system technology are the cabins brought into the garages. Otherwise, when the weather improves and after a check ride, the next passengers can ride again.

The previous planning was based on data from the helipad at the university hospital. The wind measurement system there provided the result for a period of one year (April 2019 to April 2020) that very strong winds that would have affected the cable car blew on 7 days, but the wind only blew across the axles on 4 days. For the time being, the planning therefore assumes a maximum wind-related downtime of around 7 days per year. Further wind measurements will be taken in the course of further planning.

No, in the event of a thunderstorm, operations are suspended, all gondolas are brought to the stations and all passengers must disembark. Operations are suspended until the storm has passed. The ride then continues.

A daily operating time of 17 hours is planned for the cable car all year round, plus 1.5 hours before and after, for example to transport the cabins to the garage. During the core time between 5.30 a.m. and 9 p.m., the cable car will transport passengers in any case, so that many employees working shifts will also benefit. The remaining operating hours will be determined by the operator at a later date. If far more or far fewer people use the cable car than previously planned, the operating hours could also be extended or shortened.

The calculations for the standardized assessment - in coordination with the federal and state governments and the Rhineland Transport Authority (NVR) - specify the personnel requirements for station support as follows

• two machine operators (station support) at 18.5 hours/day
• three station attendants (station support) at 18.5 hours/day
• three ward staff (ward care) at 17.5 hours/day

The personnel requirements were calculated on the basis of experience from other cable cars.

Accessibility is a major advantage of a cable car. The sufficiently large cabins can be used by passengers with limited mobility. All stations are barrier-free. In the stations, the cabins move so slowly that all passengers can get on and off without any problems and the transition between cabin and platform is also level.

The cabins offer space for ten people and there is a bench seat with five seats on each side that can be folded up. This creates space for a bicycle, baby carriage, wheelchair, etc. space can be created. Five more people can sit on the other side. Once the cable car is in operation, it will become clear whether, for example, the transport capacity will be too low during the morning rush hour due to bicycles being taken on board. If this is the case, the operator could - as is usual on buses and trains - only allow bicycles at certain times.

In any case, sufficient parking facilities for bicycles should be offered at the stations and rental bicycles should also be available.

The cable car is designed for a speed of six meters per second. At peak times, the cabins will travel at this speed, with a vehicle reaching the stations every 20 seconds, allowing 1800 people to be transported per hour and per direction. If there is less rush, the speed is reduced to 5 metres per second to minimize energy, wear and tear and maintenance costs. At this speed, 1500 people can travel per hour and direction and a cabin picks up passengers every 24 seconds.

Energy requirements vary greatly depending on the type and manufacturer of the cable car system and the drive technology used.

A study by the auditing firm PricewaterhouseCoopers (PWC) examined the traffic, technical and economic potential for cable cars in urban areas in 2022. The analysts came to the following conclusion:
"For every 100 passenger kilometers, a cable car system consumes only around 5.8 kilowatt hours (kWh), while subways consume (more than) twice as much energy at an average of 11.6 kWh and streetcars at 12.5 kWh." (Source:  https: (opens in a new tab)//www.pwc.de/de/branchen-und-markte/oeffentlicher-sektor/pwc-studie-urbane-seilbahnen-im-oepnv.pdf).

An exact calculation for the planned cable car in Bonn can only be made after the detailed planning and dimensioning of the system by the manufacturer. Based on the current plans, the administration assumes the following values:

• Schießbergweg - UN Campus installation: in normal operation, approx. 215 kWh would be required for the journeys between these stations, with start-up power in the most unfavorable load case (with fully occupied cabins and simultaneously unfavorable wind conditions) for the first hour of operation approx. 650 kWh; this would result in a maximum energy requirement of 4,090 kWh per operating day for 17 operating hours.
• Uniklink West - UN Campus plant: In normal operation, the consumption here would be approx. 175 kWh, with start-up power in the most unfavorable load case for the first hour of operation also approx. 650 kWh; on this route, a maximum energy requirement of 3,450 kWh per operating day would therefore have to be expected for 17 operating hours.

The values given are the energy consumption of the cable car system. Ancillary operations such as lighting systems, elevators and transformer stations are not taken into account.

The energy requirement was also considered in the standardized assessment: The energy requirement of the cable car in operation (both parts of the installation, based on operation for 365 days with 17 hours each) was put at a total of 4,498,625 kWh/year.

These equipment features will only be defined in cooperation with a cable car manufacturer. So far, no technical air conditioning or heating of the cabins is planned because this is not worthwhile for the rather small cabins of a monocable circulating ropeway coupled with very short travel times between the stations. The heated air would escape every time the doors are opened. In summer temperatures, windows (with ejection protection) can be opened. Additional ventilation is provided by slits in the side rails of the cabin floor at the front and rear.

The technical equipment of ropeway installations is mostly located in cordoned-off or inaccessible areas. Drive, braking, tensioning units and other technical equipment are always locked. The ladders on the supports are also locked and the cabins are safely stored in their garage at the end of operating hours. Insensitive materials are used for the interior fittings of the gondolas and the windows are coated with protective film.