Speed and Maintaining a Safe Operating area Around Trucks

Introduction

Few drivers have an understanding of the distance required to bring their vehicles to a complete stop. In our crash reports from emergency medical services we find many rear-end crashes caused by either the wrong speed for the conditions, inappropriate following distances or a lack of driver attentiveness.

The many crashes where smaller vehicles are rear-ended by heavy vehicles also reveal that our drivers have very little understanding of the increased stopping distance required by those driving heavy vehicles.

Few drivers of smaller passenger vehicles have ever been behind the steering wheel of a 50ton truck - if they have been they would never simply change lanes and cut into traffic in front of heavy vehicles.

It is important that we share a few important numbers with our drivers in alerting them to these risks and assisting them to share roads with trucks much safer!

Speed Conversion to Metre per Second

60 KM/H
16.67 Metres / Second
80 KM/H
22.24 Metres / Second
100 KM/H
27.80 Metres / Second
120 KM/H
33.36 Metres / Second
140 KM/H
38.92 Metres / Second

This speed does not relate to the size or mass of the vehicle! It relates to how far you travel in ONE SECOND!!!

Always remember, a fully laden truck will take a lot longer to stop and cover a far greater distance than a light vehicle.

Think about the braking ability of your truck !!

Read below for further information and food for thought as a Licensed Operator.

Here are some interesting facts relating to the “Stopping Distances” of UHCV’s (Ultra Heavy Commercial Vehicles.)

The following estimations are based on a 56 ton GVM on a 2% downhill gradient at 80kms /hour (22.24 metres per second)

A professional driver should always:

  • Use an engine brake or retarder.
  • Use the gears to retard the vehicle without over speeding the engine. (Green Band Driving Range)

And minimise the use of the foot brake (to prevent brake fade on a long downhill gradient)

From 80kms/hour applying correct driving skills, as per above parameters, could take up to

  • 200 Metres or 60 Seconds to bring a heavy vehicle to a standstill.
  • Remember this is not an emergency stop!!

Hence it is of the extreme importance for drivers to always maintain a Safe Operating area around their vehicle and sufficient following distances when sharing the road with trucks.

By: Hugh Sutherland & Andy Savage for ArriveAlive

Also view:

Sharing the Roads with Trucks

Collision Investigation and Understanding Brake Failure

Brakes, Braking and Road Safety

Following Distances and Road Safety

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