Nairobi, Kenya 1 2/22/2016 Nairobi, Kenya Second fastest growing - - PDF document

2/22/2016 1 TRB ROUNDABOUT COMMITTEE

Roundabouts Are Not Always the Solution; Experiences in Nairobi, Kenya Colin Ridding Project Director Mott MacDonald

Nairobi, Kenya

2/22/2016 2

Nairobi, Kenya

• Second fastest growing city in Africa
• Population of 3 million in Nairobi
• Population of 7.5 million in Metropolitan Area
• Expected to grow to 10 – 12 million by 2030

Nairobi, Kenya

• Approximately 1.5 million

passengers travel to the CBD daily (50% of City’s Population)

• Approximately 47% of all

commuters are pedestrians!

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Role in Kenya

• November 2014 –

June 2016

• EU funded Project
• Traffic Engineering

Capacity Building

• Overseeing new Bus

Rapid Transit System

• Establishing New

Transport Authority

• Traffic Management

Center

• Addressing

Congestion Problems!

Congestion in Nairobi, Kenya

• All routes into and out of

town suffer with serious congestion

• A 20 minute journey

during off peak periods can be 2 hours plus during peak times

• 6 lanes of traffic on a 3

lane highway!

• Population rapidly

increasing

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Congestion in Nairobi, Kenya

• Driver behavior and

Police Traffic Enforcement are major issues

• Poor roads and lack of

maintenance

Congestion in Nairobi, Kenya

Thousands of buses and matatus (minibuses), not very organized!!

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Congestion in Nairobi, Kenya

• Many

intersections are priority controlled

• r ‘4 way stops’
• Minimal number
• f signalized

intersections

• Several major

roundabouts

General Principles of Roundabouts

• Principal objective is to

minimize delay for vehicles and to maintain a safe passage through intersection

• Most efficient when traffic

flows are balanced between the arms

• Roundabouts designed to

match traffic forecast demand

ALY10

Slide 10 ALY10 Again - is this better near the beginning of the presentation?

Albanese, Luke Y, 1/6/2016

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Advantages

• Keep traffic moving

with minimal delay

• Aesthetically

pleasing

• Slower speeds
• Fewer conflict points
• Lower maintenance

costs

Roundabouts in Nairobi

• Pressure from the media,

drivers and previous studies to remove all roundabouts

• Too dangerous for

pedestrians and cyclists

• Do not provide the expected

capacity when compared to a signalized intersection

• Poor driver behavior
• Almost zero legal compliance
• Role of the traffic police

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Roundabouts in Nairobi

• Many

roundabouts poorly designed

• No road

markings

• No yield signs

(not that anyone would yield!)

Roundabouts in Nairobi

• Higher speed

road

• No deflection
• No Yield

signs or markings

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Roundabouts in Nairobi

Untitled.mp4

Decongestion Taskforce Committee

• Ministry of

Transport, other road authorities, Police and consultants

• Set up to identify

‘quick-win’ schemes to reduce congestion in Nairobi

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Trial ‘Quick‐Win’ Scheme

• At several

roundabouts all right turning movements temporarily banned

• Worked well at

isolated roundabouts

• Not so effective

where other roundabouts in close proximity

• Nairobi County Government

eliminates roundabouts

• Nairobi Major Roundabouts

To Be Blocked From Next Week

• Nairobi County Government

implements new traffic laws to eliminate roundabouts

• Nairobi County closes the 5

Roundabouts on Uhuru Highway

Typical Headlines

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• Long

diversions

• Increased

congestion

Trial ‘Quick‐Win’ Scheme

Police Enforcement

Trial ‘Quick‐Win’ Scheme

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Trial ‘Quick‐Win’ Scheme Trial ‘Quick‐Win’ Scheme

• Heavy Rain
• Serious Flooding

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Flooding Flooding

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Flooding

• Banning of right turns

was not successful

• Media and public

pressure to remove the drums

• Currently operating as

roundabouts

• Roundabouts will be

removed and signalized intersections installed

Outcome of ‘Quick-Win’ Scheme

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Roundabouts in Nairobi

• Roundabouts not

effective in Nairobi

• Mainly due to poor

driver behavior

• Lack of Police

enforcement

• Lack of clear

markings and signing

Roundabouts in the UK

• Numerous existing

roundabouts have been converted to signalized roundabouts

• Traffic signals can

improve capacity at a roundabout

• Signals regulate traffic

flows

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Roundabouts in the UK

• Can improve

safety by managing high circulatory speeds

• Easier to

accommodate pedestrians and vulnerable road users

Latest Innovation in the UK

• Separates

cyclists from

• ther traffic
• Segregated

cycle lanes

• First in London

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Latest Innovation in the UK

• Cyclists have a

poor safety record at roundabouts in the UK

• More emphasis
• n safety
• Many other

cities implementing similar schemes

Latest Innovation in the UK

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Latest Innovation in the UK Latest Innovation in the UK

• Dutch style turbo

roundabouts

• Reduces speeds
• Single circulating

lane

• Priority for cyclists

at entry and exit lanes

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Summary

• Roundabouts very

successful in the UK, US and many countries throughout the world

• Every intersection is

different

• All solutions should be

considered

Summary

• Consider the

needs of vulnerable road users

• Roundabouts and

signals do not always mix along the same corridor

• r within a

congested urban area

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Summary

• Safety record to

be considered

• Modeling should

be undertaken

Good Safety Record

• Significant safety

benefits demonstrated in the US

• Converting signalized

intersections to roundabouts in the US have reduced the number of crashes and injuries

• A good safety record in

the UK and elsewhere

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Thank You Further information; Colin Ridding +44 121 262 4372 Colin.Ridding@mottmac.com