Page 45 - SAPEM-Chapter-10-2nd-edition-2014

South African Pavement Engineering Manual
Chapter 10: Pavement Design

E80/axle 0.4 0.4 0.2 0.9 0.9 1.2 0.5 0.8 0.8 0.7 0.7 1.0 0.7

E80/HV 1.0 3.5 4.7

Number of
vehicles 250 100 50
Weighted
Average = 1.0 x (250/400) + = 3.5 x (100/400) + = 4.7 x (50/400)
E80/HV = 0.63 = 0.88 = 0.59

= 2.09

Figure 20. E80/Heavy Vehicle

4.1.5 Traffic Classes for Structural Pavement Design
TRH16 (1991) lists seven design traffic classes. However, TRH4 (1996) makes provision for ten pavement classes.
It is recommended that TRH4 classes, as shown in Table 11, are used.

Table 11. TRH4 Traffic Classes

2
Pavement Structural Capacity Traffic Volume and Description of Traffic
Class (million standard Approximate Description
3
axles/lane) vpd
1
ES0.003 < 0.003 < 3
ES0.01 0.003 – 0.01 3 – 10 Very lightly trafficked roads with very few heavy vehicles.
Includes roads transitioning from gravel to paved roads
ES0.03 0.01 – 0.03 10 – 20 and may incorporate semi-permanent and/or all weather
ES0.1 0.03 – 0.1 20 – 75 surfacing layers.
ES0.3 0.1 – 0.3 75 – 220
Lightly trafficked roads carrying mainly cars, light delivery
ES1 0.3 – 1 220 – 700
and agricultural vehicles with very few heavy vehicles.
ES3 1 – 3 > 700 Medium traffic volume roads with a few heavy vehicles.
High traffic volume roads or roads with many heavy
4
ES10 3 – 10 > 700
vehicles.
4
ES30 10 – 30 > 2200 Very high traffic volume roads with a high proportion of
4
ES100 30 – 100 > 6500 fully laden heavy vehicles.
Notes
1. ES = Equivalent Standard Axle (80 kN) class.
2. Traffic demand converted to Equivalent 80 kN axles.
3. vpd = vehicles per lane per day. The approximate vpd per lane for ES0.003 is estimated from the structural capacity and thus
pavement class based on the following: 10% heavy vehicles, 1.2 E80s per heavy vehicle, 4% growth rate in E80s over a design
period of 20 years.
4. For ES10 to ES100 the vpd is total per direction with 20% heavy vehicles and 2 E80s per heavy vehicle.

Section 4: Design Traffic Estimation
Page 34