Download - BRT Workshop - Bus Rapid Transit and Traffic Safety

Bus Rapid Transit and Traffic Safety Luis Antonio Lindau, Director, EMBARQ Brasil Nicolae Duduta, Associate Transport Planner, EMBARQ July 12, 2013

The impact of BRT systems on traffic safety

Factors that influence safety on BRT corridors

Relationship between safety and operational performance

Summary

Mexico City Guadalajara

Bogota Curitiba

Porto Alegre

Istanbul

Delhi

Ahmedabad

Vancouver

Brisbane

Rio, SP, BH

Pereira Cali

In Brazil it comprised:

road safety audits and inspections in 5 cities

190 km of corridors

more than 2 million pax per day

A global study




Summary

Overall safety impact of a BRT Case study: Macrobús, Guadalajara

Calz. Independencia, 2007 (before BRT implementation)

Overall safety impact of a BRT Case study: Macrobús, Guadalajara

Reduction in the number of lanes

Shorter pedestrian crossings

Central median

Existing buses and minibuses replaced with a single operating agency

Monthly crashes before and after the implementation of the BRT

0

500

1000

1500

2000

2500

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3500

4000

4500

5000

0

50

100

150

200

250

Jan

-07

Mar

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May

-07

Jul-

07

Sep

-07

No

v-0

7

Jan

-08

Mar

-08

May

-08

Jul-

08

Sep

-08

No

v-0

8

Jan

-09

Mar

-09

May

-09

Jul-

09

Sep

-09

No

v-0

9

Jan

-10

Mar

-10

May

-10

Jul-

10

Sep

-10

No

v-1

0

Jan

-11

Mar

-11

May

-11

Mo

nth

ly c

ityw

ide

cras

hes

(e

xclu

din

g th

e B

RT

corr

ido

r)

Mo

nth

ly c

rash

es o

n t

he

BR

T co

rrid

or

Citywide

Crashes on the BRT

Before During BRT

construction During BRT

Impact on crashes by severity, per year

Impact on traffic fatalities

Annual fatalities in absence of BRT Annual fatalities with BRT Change in

fatalities

Baseline data

Modeled

baseline data Project data

Modeled

project data

Macrobus BRT 1 3.5 0.3 1 - 2.5

Impact on traffic injuries

Annual traffic injuries in absence of BRT Annual injuries with BRT Change in

injuries Baseline data Project data

Macrobus BRT 96.8 30 - 66.8

Impact on all crashes

Annual crashes in absence of BRT Annual crashes with BRT Change in

crashes Baseline data Project data

Macrobus BRT 2,341 1,010 - 1,331

5000

3194

1 BRT lane

2 general traffic lanes

Passenger per hour per direction (peak)

6

726

1 BRT lane

2 general traffic lanes

Crashes per year

Comparison between the bus lanes and the mixed traffic lanes

Overall safety impact of a BRT Case study: TransOeste, Rio de Janeiro

Av. das Americas 2010 Av. das Americas 2012

Overall safety impact of a BRT Case study: TransOeste, Rio de Janeiro

The layout of the BRT is very similar to Macrobus – center lanes, median stations, overtaking lanes

But the street is considerably wider (up to 100 m) and speed limits are as high as 80kmh

Impact on safety?

There is not yet enough data available to evaluate

TransOeste

However, the data so far show between 1.5 and 4.5

fatalities per month on Av. das Americas in 2012, some of

them involving BRT vehicles, which could mean an increase

in fatalities after BRT implementation

BRTs have the potential to significantly improve safety on

the streets where they are implemented

BRT systems where reductions in injuries and fatalities have

been observed include Macrobus (Guadalajara), Metrobus

(Mexico City), TransMilenio (Bogota), Janmarg (Ahmedabad)

Reductions range from 30% (Metrobus) to 70% (Macrobus)

But some systems have seen increases in fatalities (Delhi)

or have a concerning number of fatalities (TransOeste)

Overview of safety impacts




Summary

Methodology

Crash frequency models

Road safety inspections

Discussions with BRT agency safety and operations staff


Statistical models that aim to explain the differences in

crash frequencies (or crash rates) at different locations (e.g.

intersections) using variables related to geometry, traffic

volumes, land use, etc.

Commonly use a Poisson or negative binomial (Poisson-

Gamma) distribution



Variables (Xi) Coefficients (α, βi) P

Annual average daily traffic (AADT, thousands of vehicles) 0.016 0.074

Total length of all approaches to the intersection (L, meters) 0.003 0.010

Average number of lanes per approach 0.334 0.000

Cross street is through street (=1 if yes, =0 otherwise) 1.142 0.029

Major T junction (=1 if yes, =0 otherwise) 0.719 0.019

Constant -3.914 0.000

N = 133, LR χ2 (prob.) = 64.62 (0.000), Log likelihood = -141.580

Variables (Xi) Coefficients (α, βi) P

Presence of a center median (=1 if yes, =0 otherwise) -0.349 0.004

Total number of approaches to the intersection (m) 0.424 0.000

Average length of approaches to the intersection (Lavg, meters) -0.008 0.036

Average number of lanes per approach 0.492 0.000

Cross street is through street (=1 if yes, =0 otherwise) 0.820 0.000

Major T junction (=1 if yes, =0 otherwise) 0.748 0.008

Constant -1.197 0.002

N = 132, LR χ 2 (prob.) = 135.76 (0.000), Log likelihood = -141.580, chibar2 (prob.) = 341.99 (0.000)

Table 1: Severe crash frequency model for Guadalajara (Poisson)

Table 2: All crash frequency model for Guadalajara (negative binomial)

Factors influencing crash frequencies

Counterflow

Counterflow lanes were strongly correlated with higher crash frequencies across all our models


Street width and intersection size and complexity

Metrobus Line 1, Mexico City

Road width and complexity of intersections were the most important predictors of crash frequencies.


Location of bus lanes

Central median

Shorter pedestrian crossings

Fewer mixed traffic lanes

Some 4-way intersections turned into T junctions

The safety impact of large blocks

For each additional 10 m (30’) between signalized intersections: • 2% decrease in all crashes • 3% increase in severe crashes

Wider streets are more problematic for safety

Wide, complex intersections can easily become “black

spots”

The length of crosswalks is key for pedestrian safety (for

each additional meter a pedestrian needs to cross without a

median, there is a 2 to 3% increase in pedestrian crashes)

Counterflow is the most dangerous bus lane configuration

Overview of findings from data analysis

A detailed inspection of a street with the objective of

identifying safety issues

Involves walking along the entire length of a study site (in

our case, a BRT corridor) documenting problems related to

infrastructure and road user behavior

Road safety inspections

Fatalities on BRT corridors by road user type

Fatalities by Road User

Type 0%

Pedestrians 54% Car occupants

23%

Motorcyclists 10%

Bicyclists 5% Other

8%

The safest place to be on a bus corridor is inside the bus

The most dangerous: pedestrian crossing the avenue

Crossing in mid-block

Mid-block signalized crosswalk - TransOeste

Pedestrian signal timing

BRT Safety recommendations

41 41

SPEED REDUCTIONS: PEDESTRIAN CROSSINGS: INCREASED SIGNAL TIME:

To increase safety on Av. das Americas, EMBARQ proposed…

Speed at Avenida das Américas

42

Speed

• It is very difficult to control speed through signage and enforcement • Streets should be designed for their desired speed

Pedestrian bridges

Pedestrian bridges rarely work, as pedestrians prefer to cross under them

In some cases, this is due to the fear of crime (e.g. research in Cape Town

showing pedestrians are concerned of being assaulted or robbed on overpasses)

Our research shows they are not effective for safety on typical urban arterials -

no significant impact on pedestrian crash frequencies

The exception is on high-speed, high-volume roads (e.g. Autopista Norte, Bogota,

where locations with pedestrian bridges had four times fewer pedestrian crashes

Improving the BRT routes Based on EMBARQ’s recommendations…

• Stations barriers were improved to avoid unregulated and unsafe pedestrian crossings

• Install lateral barriers in the platform doors

• The city is studying to reduce speed limits from 80km/h to 60 km/h in Avenida das Américas

2011: Signalized mid-block crossing on Eje 2 Oriente, with no traffic calming. Vehicles did not stop for pedestrians.

2012: Speed hump installed before the pedestrian crossing, slowing traffic down and allowing pedestrian to cross safely.

More closely spaced signalized intersections can help avoid unsafe speeds

But drivers may disregard signals where the only conflict is with pedestrians

Speed reductions

There is often a considerable difference between how

streets are meant to be used and how people actually use

them:

Jaywalking, including crossing under pedestrian bridges,

jumping over guardrails, destroying guardrails

Crossing on red (pedestrians) or driving on red (drivers)

The key to designing safer streets is understanding road

user behavior and how the design of the infrastructure can

be better adapted to that

Overview of findings from inspections




Summary

Most safety recommendations involved speed reductions,

traffic calming, or additional traffic signals

This raises the question of how safety countermeasures

would impact the operational performance of a BRT

We illustrate the relationship between safety and

operational performance with a case study from TransOeste

Safety, operations, and capacity

The relationship between safety and operational performance

TransOeste BRT, Rio de Janeiro, Brazil

Methodology

Identified safety issues

Proposed countermeasures

Applied a microsimulation model to test the impact of safety

countermeasures on:

Operating speeds

Travel times

Speed variability



Main safety issues:

High speed road: 80 km/h speed limit

Few crossing opportunities for pedestrians

Jaywalking is a common problem



Main safety recommendations:

Lowering the speed limit to 60 km/h

Adding mid-block signalized crossings

Improving signal timing to reduce pedestrian delay



Indicator Service Baseline 60 km/h 60/30 km/h Complete

Speed (km/h) Express 32 31.5 29.6 29.6

Local 25.6 25.6 25.4 25.4

Travel time (min) Express 71 72 77 77

Local 89 89 89 89

Speed variability* Express 0.19 0.18 0.16 0.16

Local 0.16 0.15 0.15 0.16

* Speed variability is defined here as the ratio of the standard deviation to the mean commercial speed, for all

vehicles generated in the simulation. A lower speed variability coefficient indicates more reliable service.

Key finding:

Slight negative impact on operating speed and travel time



* Speed variability is defined here as the ratio of the standard deviation to the mean commercial speed, for all

vehicles generated in the simulation. A lower speed variability coefficient indicates more reliable service.

Key findings:

Potential for significant safety benefits

No impact on passenger capacity

Magnitude of operational impacts negligible compared to safety benefits

Performance indicator

Baseline Project Change Source

All crashes n/a n/a -15% to -67% Elvik and Vaa 2004

Operating speed 32 km/h 29.6 km/h -2.4 km/h Microsimulation

Travel time 71 min 77 min + 6 min Microsimulation

Speed variability 0.19 0.16 - 0.03 Microsimulation

Capacity (pphpd) 18,800 18,800 No impact Based on Hidalgo et al. (2011)

More resources on this topic WCTR Presentation:

C4-6 Public Transport Safety (Slot 6g/Room g/13:40-15:20 Tue.)

More detailed presentation on the link between safety and operational

performance using the TransOeste case study

Publications available online:

Understanding the Road Safety Impact of High Performance BRT and Busway Design Features

Technical paper including the methodology and main findings from the

crash frequency models shown here

Available online at: http://www.brt.cl/understanding-road-safety-impact-of-

high-performance-bus-rapid-transit-and-busway-design-features-2/

Traffic Safety on Bus Corridors

Safe design concepts for BRT and Busways

Available online at: http://www.embarq.org/en/traffic-safety-bus-corridors-

pilot-version-road-test (English, Spanish, Portuguese)

http://www.brt.cl/understanding-road-safety-impact-of-high-performance-bus-rapid-transit-and-busway-design-features-2/






























http://www.embarq.org/en/traffic-safety-bus-corridors-pilot-version-road-test
















Thank you

Luis Antonio Lindau, [email protected]

Nicolae Duduta, [email protected]

mailto:[email protected]

mailto:[email protected]

Download - BRT Workshop - Bus Rapid Transit and Traffic Safety

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