Page 48 - SAPEM-Chapter-10-2nd-edition-2014

South African Pavement Engineering Manual
Chapter 10: Pavement Design

Table 12. Heavy Vehicle Classification Systems Commonly Used in South Africa

Classification Light/Heavy Extended SANRAL Toll
System Light/Heavy
Equipment Dual loop with axle load
1 Single loop
requirement Dual loop Dual loop with axle load sensor sensor
Motorcycle
Light vehicles Light vehicles Light motor vehicle Toll class 1 (light vehicles)
Light motor vehicle and trailer
Two axle bus Toll class 2 (2 axle heavy
Two axle single unit vehicles)
Buses with maximum 4 axles
Short heavy (including trailer)
vehicles Single unit with maximum 4 axles
(including trailer) Toll class 3 (3 and 4 axle
heavy vehicles)
Two axle single unit with or without
Vehicle trailer (maximum 4 axles)
classes Single trailer (maximum 4 axles)
Heavy vehicles
Buses with 5 or more axles
Medium heavy Single unit and trailer with more than
vehicles 4 axles
Five axle single trailer
Six axle single trailer Toll class 4 (5 and more
axles heavy vehicles)
Five axle multi-trailer
Long heavy Six axle multi-trailer
vehicles Seven axle multi-trailer
Eight or more axle multi-trailer
Notes
1. See Section 4.2 for descriptions of the equipment.

4.3.3 Average Daily Equivalent Axles (ADE)

The average daily equivalent axles (ADE) are the average E80s per lane per Definitions of Traffic
day for the duration of the survey period. The ADE can only be calculated Parameters
directly from data from permanent WIM stations. The ADE is calculated Different road authorities can use
using Equation (4) from the total E80s for the survey period, divided by the different definitions for the traffic
survey duration and number of lanes on which the survey was done, if not parameters. Before embarking on
already accounted for, or lane distribution factors are not available. The the traffic calculations, check that
ADE is valid for the period of the survey alone. Where permanent WIM the definitions you assume are the
station data are not available, the ADE is estimated from the ADT and same as your client’s.
AADT, considering the directional splits and lane distributions.

If axle load histogram ∑ k i=1 n x LEF i
i
available: DE = duration x lanes
(4)
If axle load histogram is not E80/HV x HVV
available and E80/HV values DE =
are used: duration x lanes
where n i = Axle count in bin i (i = 1 to k)
LEF i = Load equivalency factor of bin i (from Equations 4 or 5)
lanes = Number of lanes. Only included if the lane distributions have not
already been taken into account, and lanes carry equal E80s.
E80/HV = E80 per heavy vehicle
HVV = Heavy vehicle volume for survey duration

4.3.4 Annual Average Daily Equivalent Axles (AADE)
The annual average daily equivalent axles (AADE) are the total E80s per lane for one year, divided by 365 days. The
AADE is valid for the year during which the survey was done. The AADE is calculated from the ADE.

Section 4: Design Traffic Estimation
Page 37