Autonomous electric buses could make short-range transit safer and more efficient. The problem: articulated buses or those with passenger trailers require too much energy and are not flexible enough to accommodate the highly fluctuating passenger numbers. The solution: platooning where several vehicles follow each other at short distances, the vehicles being controlled electronically. These platoons can be adapted as required to meet specific traffic needs. Researchers from Karlsruhe Institute of Technology (KIT) are working on a city bus platoon for Munich.
“In platooning, only the vehicle in front has to be steered by a driver, all others follow autonomously,” explains Professor Eric Sax, Head of the Institute for Information Processing Technology (ITIV) at KIT. The units of the platoon are not connected physically, but via information technology. The “electronic tow bar” can be decoupled easily and it is therefore easy to split and reconnect platoons. “Platooning allows us to optimally adapt bus operations to the demand – depending on the time of day or route – especially in the urban hinterland,” says Dr. Svenja Reiß of Stadtwerke München (SWM). “Since the platoons can be split and connected as dictated by demand, we can provide a tailor-made service to our passengers.”
In Munich, all buses will be replaced by electrically powered vehicles in the long term. In order to respond to fluctuations in demand for public transport on different days or at different times of day, passenger trailers have been used to date. “With electrified towing buses, enormous amounts of electric energy would be necessary to move the trailers along,” Sax states. Motorizing the trailers too, would be neither cost nor energy efficient. On the other hand, a purely electronic and information-based coupling such as that used in platooning allows connecting complete buses instead of trailers. “Since common vehicle types will be used, electrification is easier and less expensive,” the expert says.
“We are currently developing the concepts for platooning city buses and then the corresponding algorithms for their automation,” says Nicole Rossel from ITIV. These algorithms are then to be used in a bus prototype that KIT researchers will realize together with SWM and the Dutch electric bus manufacturer EBUSCO by mid-2022. It will be tested on the new test field for electrified and autonomous vehicles in short-range transit located in the north of the Bavarian capital. “Our goal is to get the new vehicles on the road by the middle of the decade,” Sax says.
The TEMPUS Project
The TEMPUS project (short for Munich test field – urban autonomous road traffic pilot experiment) with the project partners KIT, SWM, and EBUSCO, among others, started at the beginning of 2021 and is funded by the Federal Ministry of Transport and Digital Infrastructure (BMVI) with around EUR 12 million for the duration of two and a half years. The Mobility unit of the City of Munich is in charge of the project. For real-life testing of autonomous, connected vehicles in real traffic situations, the City of Munich and the Free State of Bavaria are building and operating an urban test field for autonomous and connected vehicles in the north of Munich.
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