HB SENYALITZACIÓ PROVISIONAL HBB SENYALITZACIÓ VERTICAL

The recommendations shown in the Unsealed Roads Manual by the Australian Road Research Board are shown in Table 3.23 (Department of Transport and Public Works, 2006).

Table 3.23. Recommended road widths (Department of Transport and Public Works, 2006).

AADT Road width

Less than 50 vehicles 6 m

Between 50 & 200 vehicles 7.5 m More than 200 vehicles 8.6 m

For a Road Class 4, a road width of 4m or less requires turnouts to be provided at predetermined locations to allow vehicles passing (Department of Transport and Public Works, 2006). A minimum road width of 5 m was taken as the required width necessary for two-way uninterrupted traffic flow for a Class 4 road. Table 3.24 summarises the recommended roadway width for a Class 4 road on flat and rolling terrain, according to a count of the existing vehicles per day (Department of Transport and Public Works, 2006).

Table 3.24. Recommended road widths for Class 4 roads (Department of Transport and Public Works, 2006).

Existing Traffic (VPD) Minor Roads & Tracks Formed minor roads Divisional

roads Main roads

Trunk Roads < 20 3 m1 _{4 m}1 6 m 6 m 8.6 m 20 - 50 5 m 5 m 50 – 200 6 m 7.5 m 7.5 m > 200 6 m 8.6 m 8.6 m

1 _{Turnouts should be provided to allow vehicle passing}

No traffic counts were performed for the study roads. To estimate the amount of traffic, the Stats SA website was used to investigate vehicle ownership percentages in the area.

In the 2011 census, 12.5% of households in Sane owned at least one vehicle. This translates to 21 houses with at least one vehicle, established by using the recent Google Maps count of households. The percentage of households in Mangwele that owned at least one vehicle was assumed to be the same as in Sane. This translated to nine households with at least one vehicle. It is assumed that the existing traffic on Road Link 1 is less than 20 vehicles per day (VPD), while for road link 2 it is between 20 and 50 (VPD).

In the 2011 census, 6.1% of households in Maranikhwe owned at least one vehicle. The total number of households counted on Google Earth was 371. it was thus estimated that about 23 households in Maranikwe owned at least one vehicle. It is assumed that for Road Link 3, the number of vehicles per day (VPD) was between 20 and 50. The assumed VPD for road link 4 is 50–200 vehicles.

Such assumptions can be made to make a more informed classification of the road. It was, however, decided to suggest a minimum road width of 6 m to allow for uninterrupted traffic flow, this was decided when considering that a bus and car need a minimum lane width of 3.1 m and 2.7 m each respectively (CSIR, 2000a). The

combined width then adds up to 5.8 m. The types of vehicles observed in the road links are shown in Table 3.25.

There is another village, called Aftoni, approximately 2 km from Maranikwe. Aftoni is much smaller in comparison to Maranikwe and its vehicle ownership was therefore considered negligible. The closest village west of Mangwele is Tsakani, approximately 4.3 km from Mangwele. The west side of Mangwele consists of numerous villages, and therefore of other schools as well. The vehicle ownership of these villages was not considered because the traffic distribution from the village and the locations of key facilities is unknown.

Non-motorised transport modes in rural areas normally travels on the shoulder of the road (COTO, 2012). The shoulder width available on an unpaved road can be estimated by considering the types of vehicle which travel on the specific road and subtracting that width from the total width of the road.

I.T. Transport Ltd (2002) recommends a minimum pathway width of 1.2 m for a two- way footpath. Further recommendations are listed in Table 3.26 (I.T. Transport Ltd, 2002).

Table 3.25. Observed traffic in subject road links.

Road Link 1 Road Link 2 Road Link 3 Road Link 4 Passenger cars Passenger cars Passenger cars Passenger cars Bus (twice a day) Bus (twice a day) Taxis Taxis

Pedestrians Pedestrians Bus (twice a day) Bus (twice a day) Pedestrians Pedestrians

If all transport modes are present on the study road, the road’s cross section would need to accommodate the following transport modes:

• One bus, because only two services are made per day • One passenger car or minibus taxi (same width)

The total width required would be 7 m with the roadway being a minimum of 5.8 m and the remaining 1.2 m dedicated to the shoulder width for pedestrians.

Table 3.26. Recommended path widths for non-motorised transport modes (I.T. Transport Ltd, 2002).

Path type User Traffic

volume/day Path width (m) One-way footpath Pedestrians < 50 1.0 Two-way footpath Pedestrians > 500 1.2

One-way bicycle

track Bicycles < 50 1.2

One-way track Pedestrians

Pack- animals < 500 1.4

Two-way track Pedestrian

Pack- animals > 500 2.0 Two-way bicycle

track Bicycles > 500 2.0

3.5.3.1 Measuring road link widths

The equipment used to measure the road width was a standard measuring wheel. The procedure involved driving along the road and stopping to take the cross sectional length measurement at intervals, at places where the cross section seemed to change. The start and end points of the cross section were visibly clear, as vehicles had travelled on the road and a grader was evidently used on the road for maintenance purposes (see Figure 3.6).

Due to the relatively large expenses required to adjust vertical and horizontal alignments of unsurfaced roads, it is proposed that geometric improvements be limited to the widening cross sections only. Horizontal and vertical curves, which

require a slower driving speed, should have appropriate traffic signs assigned to them. A traffic sign log was, however, not completed

3.5.3.2 Segmentation according to widths

A separate exercise for identifying homogenous segments according to measured road widths was not conducted. The measured road widths were fitted into the already identified speed segments.