Evaluation of Operational Performance and Proposal of Improvement Schemes for Two Key Intersections in

Dhaka, BangladeshK. Tang, S. Hong, S. Tanaka, M. Kuwahara

Key words: saturation flow rate, capacity, mixed traffic

① ③

BackgroundBackground

Key words: saturation flow rate, capacity, mixed traffic

Heavy traffic congestion (①:demand>capacity) on urban roads➔ Lack of systematical land use and transportation planning ➔ Mixed traffic (②) along with undisciplined user behavior (③)➔ Inappropriate traffic operations at intersections (④)

④②

Study Sites &Study Sites &

To evaluate operational performance of key intersections in Dhaka, Bangladesh, and propose improvement schemes for them to alleviate traffic congestion on urban road network

PurposePurpose➔ Inappropriate traffic operations at intersections (④)

(=capacity bottlenecks)

CBD Ⅰ Video P d fi d kStudy Sites & Data CollectionStudy Sites &

Data CollectionTwo key intersections in Dhaka, BangladeshVideo survey time: 07:30~09:30 am, July 13th, 2009 Ⅰ

Ⅳ

Camera 1 Camera 2

Ⅰ

ⅡⅤ

ⅢⅣ

Camera 1

Camera 2

CBD

CBD

Traffic flow

851

887

7

0

1003

471

3160

34295365

0

Ⅰ: 4306

Ⅴ: 876Ⅱ: 1129

Ⅲ: 4344

(Unit: veh/h or ped/h)

Ⅳ: 1745

686

27810

840

708

2878

0

758

415

402367

404 610545

Ⅰ: 1093

Ⅱ: 1362Ⅳ: 1251

325

Sonargaon

Video files

Stop-line crossing

time

Veh. type

Direct.

Predefined keys

App. & lane

Phase switching

time

Signal Control Geometric Design

Sonargaon

Improvement Schemes

Improvement Schemes

Data reduction with a resolution of 1/10 sec.

Ⅱ

Ⅲ

Ⅳ

City CenterAccess control area:

Non-commercial & small vehicles only

237567 250505

153280

Ⅱ: 1362

Ⅲ: 938

Ⅳ: 1251

(Unit: veh/h or ped/h)Shahbag

Φ1:295s Φ2:64s

)

(Ⅰ )(Ⅰ )Current

Image-processing software used for data reduction

(George 2.1)

Sonargaonredesign signal phasingshift stop-linescompact island

Shahbagredesign signal phasing

Cycle length=413s; Total lost time=54s;

(Ⅴ)

(Ⅱ)

(Ⅲ )(Ⅳ ) (Ⅲ )

Φ1:112s Φ2:28s

Cycle length=180s; Y=3s, AR=3s; Total lost time=18s

Φ3:22s

(Ⅳ )

(Ⅰ )

(Ⅲ ) (Ⅳ )

(Ⅰ )

(Ⅲ )

(Ⅴ)

(Ⅱ)

(Ⅰ )

(Ⅲ )

plan

Proposed plan

Φ1: 64s Φ2: 56s Φ3: 54s

(Ⅳ )(Ⅱ )

(Ⅰ )

(Ⅲ )

(Ⅳ )(Ⅱ )

(Ⅰ )

(Ⅲ )

(Ⅳ )

(Ⅱ )

(Ⅰ )Current plang g p g

increase taper lengths

Performance Evaluation

Performance Evaluation

Cycle length=194s;Total lost time=20s(Ⅲ ) (Ⅲ ) (Ⅲ )

Φ1:25s Φ2:26s

Cycle length=120s; Y=3s, AR=2s; Total lost time=20s

Φ3:16s Φ4:33s

(Ⅳ )

(Ⅰ )

(Ⅱ )

(Ⅲ )

(Ⅳ )

(Ⅰ )

(Ⅱ )

(Ⅲ )

(Ⅰ )

(Ⅱ )

(Ⅲ )

(Ⅳ )

(Ⅰ )

(Ⅱ )

(Ⅲ )

(Ⅳ )Proposed plan

9400 8680

9094

8158

9258 9000

10000

te, p

cu/h

Estimated saturation flow rates under the current and proposed plans

33313431 3500

4000

Estimated capacities under the current and proposed plans

ConclusionsConclusions

SFR_1: measured SFR under the current situation (red-light-running, bus stops, etc);

SFR_2: estimated SFR under the current situation by assuming disciplined user behavior (comply with traffic signals and follow lane markings, etc);

SFR_3: estimated SFR under improvement schemes, assuming disciplined user behavior;

c_1~c_3: estimated capacities based on SFR_1~SFR_3.

5243 5172 5440

4231 4433 4401

5339

4363 4553

5896 5640 5641

4614 4834 4800

5788

4758 4995

6076

7600

5800 5770

8158

0

1000

2000

3000

4000

5000

6000

7000

8000

A 1 A 2 A 3 A 4 A 5 A 1 A 2 A 3 A 4

Est

imat

ed S

atur

atio

n (D

ischa

rge)

Flo

w R

at

2247

801

2331

2015

687

1225

1541

1214

1502

2527

874

2418 2197

749

1336

1671

1324

1648

3331

1266

3051

2771

1229

2858

2392

2845

0

500

1000

1500

2000

2500

3000

A 1 A 2 A 3 A 4 A 5 A 1 A 2 A 3 A 4

Est

imat

ed C

apac

ity, p

cu/h

ContactContact

ConclusionsConclusions

Capacity could be increased by 8.5% at Sonargaon and 9.1% at Shahbag in average, if road users completely comply with traffic rules. Capacity could be improved up to 44.1% at Sonargaon and 110.2% at Shahbag through proposed schemes.

tang@iis.u-tokyo.ac.jpKeshuang Tang, JSPS Postdoctoral Research Fellow Institute of Industrial Science, The University of Tokyo

tang@iis.u-tokyo.ac.jpKeshuang Tang, JSPS Postdoctoral Research Fellow Institute of Industrial Science, The University of Tokyo

App. 1 App. 2 App. 3 App. 4 App. 5 App. 1 App. 2 App. 3 App. 4

Sonargaon Shahbag

SFR_1 SFR_2 SFR_3

App. 1 App. 2 App. 3 App. 4 App. 5 App. 1 App. 2 App. 3 App. 4

Sonargaon Shahbag

c_1 c_2 c_3