Highway Engineering

98 Highway Engineering

Road type Number of C’way width Peak-hour flow

lanes (m) (vehicles/hour)

Urban motorway 2 7.30 4000

Through route with grade- 3 11.00 5600

separated junctions, hard 4 14.60 7200

shoulders and standard

motorway restrictions

UAP1 2 6.75 3350

High standard dual carriageway 2 7.30 3600

road carrying predominantly 3 11.00 5200

through traffic with limited

access.

UAP2 2 6.75 2950

Good standard dual carriageway 2 7.30 3200

road with frontage access and 3 11.00 4800

more than two side roads per km

UAP3 2 6.75 2300

Dual carriageway road of variable 2 7.30 2600

standard with frontage access, 3 11.00 3300

side roads, bus stops and

pedestrian crossing

Table 4.16Design traffic flows for dual carriageway urban roads (2-way)

Road type Number of lanes C’way Peak-hour flow

width (m) (vehicles/hour)

UAP1 2 6.75 2950

As above 2 7.30 3250

2/3 9.00 3950

2/3 10.00 4450

3 11.00 4800

UAP2 2 6.10 1800

As above 2 6.75 2000

2 7.30 2200

2/3 9.00 2850

2/3 10.00 3250

3 11.00 3550

Table 4.17Design

traffic flows for urban

roads (1-way)

Heavy goods Total reduction on

Road type vehicles (%) flow (vehicles/hour)

UM and UAP dual carriageway (per lane) 15–20 100

20–25 150

Single carriageway UAP greater than 10 m 15–20 100

wide (per carriageway) 20–25 150

Single carriageway UAP less than 10 m wide 15–20 150

20–25 225

Table 4.18Corrections to be applied to 1 and 2-way design flows due to heavy vehicle

percentages in excess of 15%