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The fast-growing mobility is one of the most important challenges of the 21st century. To meet it, we need to factor in specific local conditions without ever losing sight of global trends. This is why HESS, over decades of close cooperation with manufacturers and operators worldwide, has developed the CO-BOLT® modular system. Continously subject to new developments, CO-BOLT®’s flexibility makes it possible to meet the most diverse needs in public transit demand. The close cooperation with exclusive license holders in specific international markets puts over 2400 top quality buses on the world’s roads every year on five continents.

The innovative system CO-BOLT® allows a simply screwed assembly of the structure without welding. The system is formed by extruded aluminium profiles with special C-shaped channels connected by means of corresponding corner pieces and clamping plates. The self-supporting structure of the body consists of two big main profiles, the roof frame profile and the side wall profile; these are connected by a number of smaller profiles. The upper section of the body is completely formed by these profiles and does not need any further panelling. Simple side flaps, easily replaceable in case of damage, cover the entire length of the lower section of the body. Front and rear section are made of glass fibre reinforced polyester mouldings. The screws spread with a two-component adhesive ensure a safe and rigid connection and prevent unintentional loosening due to vibrations. However, the loosening of the screws in case of damage is possible even after many years. Extensive tests, more than 25 years of experience and worldwide already more than 20`000 buses with CO-BOLT® structures verify the unique properties of this system (crash tests at the US Department of Transportation DOT, the ECE 66 roll-over test as well as a considerable number of further fatigue and fracture tests were executed by recognised institutions).

CO-BOLT® has many benefits relating to investment issues, bus handling, servicing, life cycle costs (LCC) and the environment:

  • a long, problem-free service life
  • rapid and simple repairs
  • a high loading capacity thanks to the light construction
  • exactly fitting replacement parts
  • optimal anticorrosion properties
  • use of more than 80% recycled aluminium


  • excellent energy absorption in the case of a crash
  • a structure made out of extruded aluminium profiles in the CO-BOLT® module
  • system connections by means of corner supports and clamping plates
  • screw locking device with a two-component glue
  • the screws can easily be released at any time for repair work
  • the side walls are prefabricated, roof with all components ditto
  • front, rear and roof covering made out of glass-fibrereinforced plastic