Post on 12-Sep-2014
description
Designing for Safety
Demonstrating best practices for road design in the urban Indian
contextBinoy Mascarenhas
Manager – Urban TransportEMBARQ India
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people lost their lives on our roads in 2013
140,000+
Road fatalities in India
Pedestrians + Motorised 2-wheelers
typically make up half of road fatalities in cities
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What’s causing these accidents?
Human
ExternalVehicle
An accident is a rare, random,
multi-factor event
If one of the factors is corrected, it is likely that the accident would not happen, or at least, its
severity would be reduced
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What are the external factors?
Road conditions Geometry (alignment, elevation, area allocation, etc.) Pavement condition (debris, potholes, wetness, etc.) Signage & lane marking Provisions (crossings, U-turns, turning lanes, parking,
etc.) Lighting & visibility
Traffic conditions Speed Volume Mix Turning movements
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The role of junctions
Although junctions take up only a fraction of road space, they
typically account for more than half of all road accidents
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Guideline design template for junctions
Generally provided for 4-arm intersectionsRoads meet at perfect right anglesRoad width is constant across the junctionNo obstacles / encroachments on road spaceCo-planar geometry
Sometimes junctions do not meet these ideal conditions.
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Typical issues with junctions
Very large junction area
5+ arms
Roads meet at skewed angles
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Typical issues with junctions
No proper lane balance & alignment
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Typical issues with junctions
Pedestrians sharing path with traffic
Wide roads leading into narrow roads
Wide kerb radius
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Typical issues with junctions
No designated pedestrian crossings
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Typical issues with junctions
Often, road resurfacing and laying of footpath ceases just before the junction
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Thane junction improvementCase of Nitin Chowk junction
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Site location
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Existing geometry
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Pedestrian movement
Underutilised subway Pedestrians cross at-grade
No pedestrian crossing islands
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Pedestrian movement
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Ancillary road uses
Private bus pickup/drop-off Bus U-turn in the intersection
Unused auto rickshaw stand Illegal 2-wheeler parking
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Ancillary road uses
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Turning movements
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2-way service roads
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Multiple conflict points
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Wide undefined intersection area
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Design process
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Design decisions
Service roads are meant for local access; main lanes are for through movement
Use internal streets for local movement between service roads
Traffic below the flyover to be slowed down to allow for safe at-grade pedestrian crossings
Maintain lane balance & alignment on opposite sides of the intersection
Reduce intersection area, by advancing stop lines and tightening corners
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Recommended design
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Recommended design
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At-grade pedestrian crossings
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Service road entry to main lanes
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Use of internal streets to bridge connections
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U-turns after the intersection
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Proposed design
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Proposed signal plan
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Lessons learned
Junction design needs to be contextual. Rather than a standard design, a standardised process for design is required
The solution often lies beyond the junction area (traffic re-routing)
Service roads are meant purely for access, not for thoroughfare. They should NOT continue through the junction
Subways and FOBs will not work if they involve a significantly greater effort than the natural at-grade crossing path
Junction safety can be improveed while simultaneously increasing capacity
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THANK YOU!