Environmental aspects of driving and economical driving
Environmental and economical driving questions reward concrete technique and the physics behind it: how speed, mass, tyres and anticipation change fuel consumption, emissions and noise.
Smooth driving
- Accelerate progressively and change up around 1,500–2,000 rpm, using the engine's torque band.
- Look far ahead, lift off early and let the retarder or engine brake do the slowing.
- Switch the engine off during longer stops; idling burns fuel and gains nothing.
Speed and resistance
- Air resistance rises with the square of speed, so consumption climbs steeply above roughly 90 km/h.
- Rolling resistance depends on tyre pressure and load; under-inflated tyres cost several per cent of fuel.
- Air conditioning and added roof equipment increase consumption; use climate control sensibly.
Technology and emissions
- Modern buses meet EURO VI using SCR with AdBlue and a diesel particulate filter; both need the correct fluid level and regeneration cycles.
- Emissions-system warning lamps are a technical and an environmental fault at the same time.
- Correct maintenance - filters, injectors, oil - keeps consumption and smoke low.
Noise and surroundings
- Quiet driving at night, gentle door operation and no revving at stands.
- Keep the bus clean and free of leaks; spilled oil or fuel is environmental damage.
Worked example
Two drivers cover the same 500 km route. The first accelerates hard and brakes late: 30 l/100 km, i.e. 150 l. The second drives smoothly: 26 l/100 km, i.e. 130 l. The saving is 20 l, roughly 700 CZK at 35 CZK/l, plus less brake and tyre wear - and the smooth driver's average speed is barely lower.
Traps
- Long idling "to warm the engine" - modern diesels warm up while driving.
- Believing a higher gear always saves fuel, even when the engine labours.
- Ignoring under-inflation because it is not a legal defect.
- Forgetting that a full bus burns more and needs earlier gear changes.