Formula 1 cars have energy recovery for kinetic energy (regenerative braking) and thermal energy (motor generator unit in turbocharger shaft). Both of these technologies have potential to be used for buses and other heavy vehicles that move in an urban environment.

As an example, my regular bus route is 50% highway at 80 km/h and 50% urban start-stop traffic. The city buses have a huge turbo diesel or natural gas engine, and the turbo takes about 3 seconds to spool up. At 80 km/h, drivers tend to be pumping on and off the throttle, purging the turbo pressure repeatedly. This is horrible for fuel efficiency.

Ideally, an electric motor should do the initial few seconds acceleration, while the turbo is being spooled up using the electric motor attached. When the turbo is spools up, the internal combustion engine should be slowly introduced by adding fuel according to the correct stoichiometric ratio. At cruise speeds, engine power could be regulated by harvesting energy off the turbine rather than pumping the gas pedal which purges the whole turbo.

A city bus should be able to operate at or near optimum stoichiometric conditions at all times, saving a ton of gas and emissions. Currently there's a huge puff of black diesel smoke every time the bus leaves a bus stop.

These are very exciting times for anyone who is interested in motor sports technologies applied to efficient transport.