Lecture 3 - Priority Intersections

Question 1

What is a priority intersection?

Answer 1

• Intersection between minor/major road traffic
• intersection usually controlled by stop signs, give way and road markings
• Less delay for vehicles on main road

Question 2

What is the design standards and guidance?

Answer 2

DMRB & Manual for Streets

Question 3

Types of priority intersections?

Answer 3

• Cross roads
• skew or y junctions
• staggered junctions
• T-junction

Question 4

Forms of priority intersections?

Answer 4

• Dual carriageways
• Simple layouts
• Ghost island layouts
• localised single lane dualling

Question 5

Forms of Priority Intersections - Simple layout

Answer 5

• not suitable, evidence of accidents involving right turns.
• Major road traffic is restrained by right turns into the minor road.

Question 6

Forms of Priority Intersections - Ghost island layouts

Answer 6

• Designated space for vehicles from major roads turning into minor road.
• Avoid use: overtaking opportunies

Question 7

Forms of Priority Intersections - Dual carriageways

Answer 7

• Not to be used on new dual-3 all purpose roads.
  -Should include the widening of the central reserve to give an offside diverging lane

Question 8

Forms of Priority Intersections - Localised single lane dualling

Answer 8

• Generally used on rural single carriageway roads
  -Useful where a pedestrian crossing required to

Question 9

what can you do If road safety issues likely to arise from overtaking on single carriageways?

Answer 9

• Reduce the carriageway width
• Use different coloured surfacing materials
• Use double white lines along the hatching boundary at ghost islands intersections

Question 10

Where should priority intersections be located?

Answer 10

• Do not position priority intersections on sharp bends
• Where locating priority intersection in a bend is unavoidable, T-intersections should be sited with the minor road on the outside of the curve
• Cautious thought: priority is not mistaken at skew junctions
• Ideally to be located on level ground or where approach gradients is not more than 2% uphill or downhill

Question 11

What are some safety considerations?

Answer 11

• Safeguarding pedestrians and making particular provision for cyclists
  -Inhibiting overtaking on the approaches
  -Making crossroads more visible or changing them with staggered intersections
• Enhancing visibility
  -Prohibiting right turning, especially on high speed carriageways