Speed

Encouraging drivers to slow down improves fuel efficiency and road safety.

How speed affects fuel efficiency

Vehicles need more power, and fuel, to drive at higher speeds. Reducing peak speed by just 8 km/hr save 10% to 15% in fuel consumption.

Braking and accelerating also use a lot of power and fuel, which is why maintaining an average speed saves fuel compared with driving at higher speeds. The power needed to stay moving at 90 km/hr is 20% less than that for 100 km/hr.

This example from CablePrice (NZ) Ltd and Scania CV AB illustrates the effect of speed on fuel consumption of a large truck:

SpeedFuel consumption
70 km/h  27 litres/100 km
80 km/h 30 litres/100 km
90 km/h  34 litres/100 km 

70 km/h 27 litres/100 km 80 km/h 30 litres/100 km 90 km/h 34 litres/100 km

Benefits of slower driving

  • Significant fuel savings
  • Improved road and driver safety
  • Fewer driving infringements
  • Fewer repairs from collisions and insurance claims
  • Lower maintenance costs, including reduced tyre wear
  • Less driver fatigue
  • Higher profits

Driving styles

Drivers who run at high speeds have to brake more often and for longer for curves and other road and traffic conditions. Accelerating back up to those speeds takes considerable power and uses more fuel.

Driving smoothly and anticipating conditions ahead reduces sudden stops and starts, improving average speed. It’s common for drivers to report savings in trip time and to feel less tired and stressed when they drive more consistently.

Adopt a non-speeding culture

Moving to a non-speeding culture effort needs buy-in from managers and dispatch staff as well as drivers themselves. Many transport operators don't tell drivers that they mustn’t speed - some encourage speeding by putting too much pressure on their drivers. Ministry of Transport statistics from 2014 show that speed was the main contributing factor in 6% of heavy truck crashes.

Tips for changing culture

Look for ways to save time during loading and unloading to take pressure off drivers.

  • Tell drivers not to speed. Use staff meetings and posters in the lunch room or dispatch offices to remind both drivers and dispatch.
  • Use the speed limiters to save fuel.
  • If your vehicles have GPS, monitor speeding events and give drivers feedback. Reward the group for significant progress.
  • Work with clients to get flexibility in arrival times. Calling ahead to alert a customer to a delay allows a driver to focus on driving safely instead of watching the clock.