Improving Intercity Bus Reliability by Automatic Vehicle Location and Vehicle Infrastructure Integration

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Chung-Jen HsuPh.D. studentAdvisor : Elizabeth G. Jones 10/21/2008

18TH NATIONAL RURAL PUBLIC AND INTERCITY BUS TRANSPORTATION CONFERENCE

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Content

• Introduction• Bus Travel Time Analysis• Passenger Travel Time Analysis• Solution• System Architecture and Operation• Conclusion

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Introduction

• Reliability is a key factor• Arrival Time Estimation• Previous Research Review• Systematic Approach• Automatic Vehicle Location (AVL) + Vehicle Infrastructure Integration (VII)

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Bus Travel Time Analysis

• Link travel time• Intersection delay time• Stop dwell time • Time-point waiting time

Stop Time PointIntersection

Start End

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Acceleration time TA = VC / a

Deceleration time TD = VC / d

Cruise time TC = (L – VC / 2a – VC / 2d) / VC

Link travel time TL = TA + TC + TD

VC : Cruise speed

a : Acceleration rated : Deceleration rate L : Link length

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TR = ∑ TL + ∑ TI + ∑ TS + ∑ TW

TR : Route travel time

TL : Link travel time

TI : Intersection delay time

TS : Stop dwell time

TW : Time point waiting time

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Passenger Travel Time Analysis

• Time to stop• Waiting time• Onboard time• Time to destination

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Solution

• Accurate estimation of bus arrivals• Bus information accessibility by Internet, cellular phone • Bus information provided at stops and on- board

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G R G

R

G G

R

G G

R R

R

Y

Time

Space

YY

YY

YY

Y

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RSE

DSRC Communication Range

: GPS Data Point

: VII Data Line

VII DSRC StandardSAE J2735 (draft)

VII snapshots• Stop/start• Depend on speed

Speed RSE Spacing

Time between

snapshots

<20mph 1 miles 6 secs

20-60 Linearly spread

>60mph 10 miles 30secs

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System Architecture and OperationBus GPS Data • Time• Longitude• Latitude

Database• Bus No.• Time• Longitude• Latitude

Calculate Travel time• Link No. , travel time• Stop No. , dwell/waiting time• Intersection No. , delay time

Generate Stops Arrival Time• Route No.• Stop No.• Arrival time

Electric Bus Stops • Route No.• Bus No.• Arrival time

VII Dwell TimeDSRC

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IVR

Electronic Bus Stop

System Server

Bus

GPS

DSRC

Wireless Network

Cellular Network

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Conclusion

• An innovative architecture of integrating AVL and VII technologies was proposed to improve intercity bus reliability. • Bus arrival time at each stop can be predicted with high precision with implementation of the system.• Electronic Bus Stop and backend Interactive Voice Response system provide accessible information to en-route passengers. • The system needs to be implemented to analyze the level of improvement to intercity bus reliability.

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