--- title: "Major urban road patterns" subject: "Transportation Engineering I" chapter: 1 key: "semester_6/transportation_engineering_i:urban-road-patterns" source: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/urban-road-patterns site: BCT Engineering --- # Major urban road patterns Transportation Engineering I · Chapter 1: Introduction to Transportation Planning and engineering - Asked in: 2081 Ashwin, 4 marks; 2079 Ashwin, 4 marks; 2077 Chaitra, 4 marks; 2071 Bhadra; 2066 Magh (old course), 8 marks (asked 5 times) - Video: [Every Major Street Pattern Explained in 9 Minutes](https://www.youtube.com/watch?v=OBl6n6ECVUA) — Urban Planner Explained - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/transportation_engineering_i/urban-road-patterns - Whole chapter: https://www.bctengineer.com/md/semester_6/transportation_engineering_i/chapter-1 ## Question Explain the major road patterns developed in urban areas (urban network planning) with neat sketches. ## Short answer Common patterns are rectangular (grid), radial, radial-circular (ring-radial), hexagonal, and linear. Grid is simple but has many conflicts; radial gives direct centre access but causes congestion; ring-radial diverts through traffic. ## Answer Urban road patterns are the arrangements of streets and arterials that form the road network of a city. The common patterns are listed below. #### 1. Rectangular (grid-iron or block) pattern ```text | | | | | --+---+---+---+---+-- | | | | | --+---+---+---+---+-- | | | | | ``` - Roads cross at right angles, forming rectangular blocks. - Advantages: simple, easy land subdivision and direction finding, many alternative routes. - Disadvantages: many 4-way junctions (more conflicts), long travel between diagonal points, monotonous. Example: Chandigarh. #### 2. Radial (star and block) pattern ```text \ | / \ | / ----- (CBD) ----- / | \ / | \ ``` - Roads radiate from the central business district (CBD), with the areas between them divided into blocks. - Advantage: direct access to the centre. Disadvantage: traffic congests at the centre, and the radial arms are poorly connected to each other. #### 3. Radial-circular (ring-radial, star and circular) pattern ```text ___________ / _______ \ / / \ / \ \ | |--- O ---| | \ \__/ \__/ / \_____________/ ``` - Radial roads plus one or more concentric ring roads. The ring roads divert through traffic away from the centre. Example: Delhi, Kathmandu Ring Road. #### 4. Radial-grid (star and grid) pattern - Radial roads from the centre are combined with a grid of streets between them; gives direct routes to the centre and easy subdivision of land. #### 5. Radial-web (spider-web) pattern - Radials linked by circumferential roads of polygon shape; similar to ring-radial but with direct links. #### 6. Hexagonal pattern - Roads form hexagons, with only three-way junctions at 120 degrees; this reduces conflict points, but travel distances are longer and the layout is difficult to set out. #### 7. Minimum travel pattern - The city centre is surrounded by sector centres and suburban centres linked by ring and radial roads, laid out so that the total travel between them is a minimum. #### 8. Linear (ribbon) pattern - The city grows along a main road or river (e.g. along a highway); simple, but the main road becomes overloaded. #### 9. Irregular (organic) pattern - A mixed pattern that develops over time with the terrain (typical of old Nepali towns like Bhaktapur and Patan). | Pattern | Best feature | Main drawback | |---|---|---| | Grid | Easy planning | Many conflicts | | Radial | Direct to centre | Centre congestion | | Ring-radial | Diverts through traffic | Needs land | | Hexagonal | Few conflicts | Hard to set out, longer trips | ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. What is a main disadvantage of the rectangular (grid-iron) pattern? A. Hard to subdivide land B. Few alternate routes C. Poor direction finding D. Many 4-way junctions causing more conflicts and long diagonal trips Answer: D. Grid roads give many 4-way junctions (more conflicts) and long travel between diagonal points, though planning is simple. (Key point: Grid pattern drawbacks) 2. What is the chief drawback of the radial pattern? A. Traffic congests at the centre and radial arms are poorly connected B. No access to the centre C. Too many ring roads D. Only three-way junctions Answer: A. Radial roads give direct access to the CBD but concentrate traffic there. (Key point: Radial pattern problem) 3. What is the role of ring roads in a radial-circular pattern? A. To increase traffic entering the centre B. To divert through traffic away from the centre C. To remove radial roads D. To make the city linear Answer: B. Concentric ring roads divert through traffic from the centre, though they need land. (Key point: Ring-radial pattern purpose) 4. What characterises the hexagonal pattern? A. Only four-way junctions B. Roads growing along a single river C. Three-way junctions only, reducing conflict points but hard to set out D. Irregular layout following terrain Answer: C. The hexagonal pattern has only three-way junctions giving fewer conflicts and shorter routes, but is difficult to lay out. (Key point: Hexagonal pattern) ## Related in Transportation Engineering I - [Urban road networks and ring road](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aurban-network-ring-road) — Transportation Engineering I, chapter 1, asked 2× - [Urban road cross-section elements](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aurban-road-cross-section) — Transportation Engineering I, chapter 3, asked 2× - [Objectives of road planning](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Aobjectives-road-planning) — Transportation Engineering I, chapter 1, asked 4× - [Hill road drainage structures](https://www.bctengineer.com/question.md?key=semester_6%2Ftransportation_engineering_i%3Ahill-drainage-structures) — Transportation Engineering I, chapter 5, asked 4× ## Related in other subjects - [Underground feeder economical in urban areas](https://www.bctengineer.com/question.md?key=semester_8%2Ftransmission_and_distribution_system_design%3Ajustify-underground-urban-economical) — Transmission and Distribution System Design, chapter 5, asked 4× - [Network planning for remote area telephony](https://www.bctengineer.com/question.md?key=semester_8%2Ftelecommunications%3Anetwork-planning-remote-area) — Telecommunications, chapter 1 - [Quality control in urban road construction](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Aquality-control-urban-roads) — Project Engineering, chapter 4 - [CPM network, road project (days)](https://www.bctengineer.com/question.md?key=semester_7%2Fproject_engineering%3Acpm-network-road-project-b79) — Project Engineering, chapter 3