Urban Street Design: Pedestrian & Vehicle Space Optimization
Street and Pedestrian Space: Urban design should prioritize both pedestrian and vehicle mobility. Street treatments must maintain pedestrian continuities, avoiding isolated interventions. Pedestrian routes should accommodate diverse activities, creating versatile and adaptable spaces. These spaces should be comfortable, safe, and environmentally suitable.
Pedestrians require a minimum of 0.60 meters of space on a sidewalk. Recommended widths are:
- 1 person: 0.75 m
- 1 person with a stroller: 0.90 m
- 2 people crossing: 1 m
- 1 person: 0.60 m (minimum)
- 1 person with a buggy: 0.80 m
- 2 people crossing: 0.90 m
- 2 people walking parallel: 1.30 m
Sidewalk slopes should not exceed 12%, ideally remaining between 6-8%. Longer sections and steeper inclines may require mixed ramp and stair solutions.
Pedestrian spaces, primarily sidewalks, can be symmetrical or asymmetrical. Arcades and central reservations are common in boulevards, avenues, and pedestrian streets. A functional analysis helps define the overall width by considering the desired pedestrian space.
Four Types of Pedestrian Bands:
- Traffic Band: For pedestrian circulation, free of barriers, with street lighting and urban furniture. It should have a continuous longitudinal design.
- Estancial Band: Used for various activities like waiting, resting, or playing. This design considers the street as a place, not just a transportation channel. These areas can be interconnected islands.
- Building Easement Band: This space, usually 0.5 meters wide, acts as a service sidewalk for the building. In commercial streets, it can range from 1 to 3 meters.
- Sidewalk Easement Band: A 0.5-meter transition zone between the road and sidewalk where parking is allowed.
Separation between road, easement, or estancial and access areas is usually achieved with vegetation, interrupted at intervals for passage.
Recommended Sidewalk Widths:
- Main streets and wide avenues: 5 to 7 m
- Commercial streets: 5 to 7 m
- Local or collector/industrial distributor streets: 3 to 5 m
- Residential local streets: 2.5 to 3 m
- Industrial local streets: 2 m
The minimum value is independent of the underground environment. Lower values are acceptable only if car service stops do not impede pedestrian movement. Central boulevards should be at least 9-12 m wide, ideally no less than 15 m.
Vehicle Movement (Road):
The road is designed for vehicle traffic. Modern road design considers dimensions, driving conditions, and maneuvers. Basic vehicle dimensions (width [A], length [L], inner radius [ri], outer radius [rs], and space [s], all in meters) are crucial for design.
- Midsize car: A: 1.70, L: 4.20, ri: 3.4, rs: 5.80, s: 0.36
- Large car: A: 1.80, L: 4.90, ri: 6, rs: 8.85, s: 0.40
- Light commercial vehicle: A: 2.20, L: 7, ri: 8, rs: 11.40, s: 0.60
- Truck (2 axles): A: 2.50, L: 9, ri: 8.50, rs: 12.50, s: 0.70
- Bus: A: 2.50, L: 12, ri: 10, rs: 13.60, s: 1.40
- Trailer: A: 2.50, L: 15-16.50, ri: 6, rs: 12-13.50, s: 0.35
Maneuvers, including 90, 180, and 360-degree turns, and parking, are essential design considerations. Vehicle size and maneuverability are critical for street design. The standard carriageway is divided into sections, with denser movement leading to greater road occupancy. Lane sizing should avoid oversizing or under-dimensioning, considering the traffic and the presence of slow vehicles. Streets typically range from 3 to 3.5 meters wide.