FAQ

Why am I getting the following warning 'Curve Not Traversable' ?

If you receive this warning message in the Design tab, it is because the specified truck(s) do not have enough braking force requried to travel safely down the segmenat. Two critical components must be considered in calculating the total braking force required:

Weight Component (Gravitational Force): This is the force that the brakes must overcome just to prevent the truck from accelerating downhill due to gravity. It can be thought of as the minimum force required to maintain speed or prevent acceleration.

Deceleration Component: This is the additional force required to actually slow the truck down at the specified deceleration rate. When you want to achieve a certain rate of deceleration, you need to account for the inertia of the truck. The faster the truck is moving or the heavier it is, the more braking force will be required to achieve the desired reduction in speed.

info

Worked Example

$\text{Truck Weight} = 385,000 \, \text{kg}$
$\text{Slope} = -12\%$
$\text{Rolling Resistance} = 2\%$

Weight Component

$\text{Angle} = arctan((12-2)/100) ≈ 5.7^\circ$
$\text{Weight Component} = 385,000 \times \sin(5.7) = 38,308 \, \text{kgf}$

Deceleration Component

$\text{Max Deceleration} = \frac{1.5}{3.6} = 0.41667 \, \text{m/s}^2$

$\text{Deceleration Component} = \frac{385,000 \times 0.41667}{9.81} = 16,369 \, \text{kgf}$

Total Force

$\text{Total Force} = 38,308 + 16,369 = 54,677 \, \text{kgf}$

If the truck uses the following braking curve, it can be seen the maximum braking force avaiable is 50,000 kgf which is below the 54,677 kgf needed.

The brake curve indicates that there isn't enough braking force to safely traverse the downhill segment.

Why can't I report Cylcle Times ?

The simulation's Dispatch engine dynamically assigns trucks after they dump their load, meaning there is no guarantee that a truck will return to the same source loader. As a result, reporting cycle time is not meaningful since complete cycles may not always occur.

Within the Destination reporting source, the value field 'Average Loaded Haul Duration (minutes) Total' represents the average time taken for loaded travel from a source to a destination.