Bus Rapid Transit Infrastructure Design Roadway and Junctions Bus stops Shreya Gadepalli Senior...

Bus Rapid TransitInfrastructure Design

Roadway and JunctionsBus stops

Shreya GadepalliSenior Program Director

Institute for transportation and Development Policy

Roadwayand

Junction Design

Intersections are criticalSO REDUCE CONFLICTS

Restrict turning options where possible (no right turns)

Avoid elements which can be put elsewhere (No parking near intersection +

Shift back BRT stations)

Provide time for pedestrians to cross and safe places to wait

General traffic capacity along a corridor

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60

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0 200 400 600 800 1000 1200meters

real

tivec

apci

ty %

Two phase signal

traffic direction

four phase signal

INTERSECTION CAPACITY varies with signal phasing

Signalized

Round about

(square geometry)

All turning movements possible in two signal

phases

Higher junction

capacity

Lower time lost for BRT as well as mixed

traffic

TWO PHASE OPTIONS

TWO PHASE OPTIONS

Signalized

Round about

(square geometry)

Size based on turning movement volume

Signal cycle an essential component of geometric

design

Short signal cycle essential avoid jam

Short signal cycle gives frequent pedestrian

crossing time

Signalized round about (Split

intersection)

Two Phase signal phase

Higher junction capacity

Multiple arms incorporated

TWO PHASE OPTIONS

Only straight movement allowed at

junction with two phase signals

Right turning movement through

U-turn - Left turn combination

TWO PHASE OPTIONS

BUS STATION LOCATION

Pedestrian behavior at junction

BUS STOP

BUS STOP

Bus blocks bus bay due during Red Phase not letting buses behind to access the bus stop

Risky behavior of Pedestrians to access the bus station

Pedestrian has to get across MV traffic of multiple directions in unsafe conditions

Fewer lanes for MV traffic at junction results in longer cycle time and lower junction capacity

Fewer lanes to cross to reach BRT station

Median Station allows for easy transfers

More space for mixed traffic at intersection

Synchronized signals for safe pedestrian crossing

BRT STOP AT INTERSECTIONBRT STOP AWAY FROM INTERSECTION

BUS STATION LOCATION

JUNCTION DESIGN

If BRT Station is at the Junction then

Many buses cannot utilize GREEN signal since earlier bus blocks the bus bay because it is waiting at the RED signal

Results in Long queues and bunching of buses and slows down the BRT system

May result in unwanted pedestrian behavior wishing to reach bus stop

BUS STATION LOCATION

Station setback from Intersection

Station at Intersection

BUS STATION LOCATION

BRT Stations

Speed vs saturation

B Rapid T B Slow T35

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15

10

5

0

spe

ed

(km

/h)

saturation

0 0.1 0.2 0.50.40.3 0.80.70.6 10.9

cars

buses

BUS STATION SATURATION

BUS STATION CAPACITY

Increase in capacity with overtaking lane

Large bus flows with inadequate infrastructure causes huge bunching

Multiple bus bays with overtaking lane for entry exit as well as express services

reduces bus stop saturation and increases system capacity

Open bus platforms do not regulate where buses stop.This creates confusion at the station

Narrow overtaking lane obstructs oncoming buses and mixed traffic lanes – minimum width at bus station location with overtaking lane > 7m

LANES AT BUS STATIONS

Lane width requirement

Platform not properly aligned and only one door per bus at each station.

Undersized stations for actual demand

This caused crowing at inside stations

Bus queuing even at very low capacity (3000 pphpd)

Higher demand exists on the corridor so other buses ply in mixed traffic

BUS STATION CAPACITY

Station dwell time and capacity

BUS STATION SIZE

Waiting space inside bus station

One size does NOT fit all

Estimating passenger boarding and alighting demand of each bus stop location is important for bus station sizing.

Small and Narrow station

Creates large passenger queues outside the bus station

Results in discomfort and reduced efficiency of boarding

What it should be What it should NOT be

At level boarding

Maximum gap of 10cm between bus floor and Platform

BUS STATION PLATFORM

BUS STATION FEATURES

High ceiling with partial roof cover over Bus

Safe distance between Bus and

BRT station

(250mm)

System Identity and Station Name

Route information

Platform extension for close docking

of bus

(<125mm)

DOES SPEED MATTER?

• Most mass transit options can have relatively similar operating speed, other aspects remaining similar

• Speed is important since the fleet size required becomes lower for the same frequency of service

• Average speed increases as distance between stops increases. But speed of system matters only so far as total trip time of passengers is reduced

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0 4 8 12 16 20 24 28 32 36 40 44 48 52

Time (sec)

Dis

tan

ce(m

) / S

pee

d (

kmp

h)

Speed curve

Distance traveled between stops

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25

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374 475 575 676 777 878 979 1079

Distance between stops (m)

Av

era

ge

Sp

ee

d (

km

ph

)

Stop spacing and Passenger trip time

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5

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40

Length (km)[Stop spacing

500m]

Time (min) [Stop spacing

500m]

Length (km)[Stop Spacing

1000m]

Time (min) [Stop Spacing

1000m]

Dis

tan

ce

(k

m)

/ Tim

e(m

in)

End of trip Walk

In vehicle time

Waiting time

Start of trip Walk

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4 6 8 10 12 14 16

Total trip length (km)

To

tal t

rip

tim

e (m

in)

Stop spacing500m

Stop spacing1000m

• When trip lengths are short, closely placed stations are preferable since slow speed walk time becomes a large component of total trip time.

• As trip lengths increase, system speed can be increased by increasing station spacing

Bus Speed Profile vs Average Commercial Speed

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80

0 6 12 18 24 30 36 42 48 54 82 88 94 100

106

112

118

124

130

Time (Sec)

Sp

eed

(km

ph

)

BRT and Pedestrian

PEDESTRIAN CROSSING every 120-200m

else they will make their own crossing!

Pedestrian Delay

Over 30 sec – Risky Behavior

Over 60 sec – would surely attempt to cross

Very long signal cycles with long waiting time for

pedestrians makes them take chances and meet with

accident.

Lower pedestrian delay requires shorter signal cycles

Zebra crossing Median treatment

Which one is better?The Answer is evident

At grade access to bus stops

HCBS Junction Conceptual Design

Waiting space for NMV in front of MV

Larger Pedestrian crossing space

No free left turns

-10

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0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80

Motor vehicle speed (km/h)

Perc

ent

Minor Injury

Major Injury

Death

Poly. (Major Injury )

Poly. (Death)

Poly. (Minor Injury)

Speed vs Injury

Removing free left turns will reduce

Left turn crashes by 19 %Collisions with pedestrians by 38%

Collisions with cyclists by 50%

Pedestrian Safety

Speed Drop Collision Drop

2 km/h 5%

5 km/h 15%

10 km/h 42%

5% Speed drop results in

15% fewer collisions10% fewer pedestrian fatalities 20% less severe pedestrian injuries

Left turning speed and turning radius

Target turning speed

Trucks < 10 km/hCars < 20 km/h

Effective Turning Radius

Use 4.5 m compound curve

NOT 15 m simple curve which results in 30-35 km/h

for cars)

High Vehicle speed but low visibility of Pedestrian

Unsafe

Left turn slip lane design

Lower Vehicle speed with better visibility of

Pedestrian

Safe

Slip lanesWhat they should NOT be

UNUSED but UNSAFE

Observing existing road use can teach

us a few things about safe and

realistic geometry

Fantasy

Make drivers and pedestrians behave

Develop a cleaner and quieter engine

Design city so everyone drives everywhere all the time

Build more capacity to move out of congestion

Something to think about

Reality

Eliminate or reduce severity of crashes

Minimize pollution and noise

Recapture urban space for people

Effectively utilize existing infrastructure

Vehicle speed Speed is a significant determinant of severity of crashes, should be logical

with respect to context, and is a critical factor in safety where there are conflicting traffic modes.

Lower vehicle speeds open a range of design options that enable a street to look less like an expressway and more like a neighborhood

street.

Pedestrian and bicycle exposure riskBy making the distance to cross the street shorter, the time spent

crossing the street is reduced and the exposure risk is subsequently reduced.

Driver predictabilityIf other street users can better predict how and where a particular

vehicle will be driven, the street will be safer.

3 Principals to remember