smarter transit system via connected vehicles and low cost ... brian park... · in assessing or...
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Smarter Transit System via Connected Vehicles and Low Cost
Internet of Things
June 21, 2018 B. Brian Park
Link Lab University of Virginia
Presented at the 5th Summer Conference on Livable Communities
Connected Vehicle based Transit Signal Priority
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What is TSP
! Transit Signal Priority (TSP) " A control strategy that offers preferences to transit vehicles
at signalized intersections
! Conventional TSP Challenges " Adverse effect on side streets " Minor benefit " Few buses can take advantage " Uncertainty of benefit " Not accommodating conflicting TSP requests
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Why TSPCV
! Incorporate V2X technology " Transit Signal Priority with Connected Vehicle (TSPCV) " Two-way communications " better real time traffic information " More accurate arrival time prediction " Advanced TSP logic would be possible
! Recognized as “Day 1 application” " AASHTO, USDOT …
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TSPCV Logic
! Strategy " Green time reallocation
• Most buses are covered
! Bus cooperates with the traffic signal to perform TSP
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Green Reallocation
Queue cleared/ Bus arrival time
Bus arrival time range
Corresponding Green start time
Respect the original Phase
transition points Move part of the green forward
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Objective Function
! Minimize ( ∑𝑐𝑦𝑐𝑙𝑒=1↑𝑐𝑦𝑐𝑙𝑒=𝒏▒𝐷↓𝑖 ∗𝑂𝑐𝑐↓𝑖 +∑𝑐𝑦𝑐𝑙𝑒=1↑𝑐𝑦𝑐𝑙𝑒=𝒏▒𝐷↓𝑏𝑢𝑠 ∗𝑂𝑐𝑐↓𝑏𝑢𝑠 ) " subject to: " ∑𝑗↑▒(𝐺↓𝑗𝑏𝑒𝑓𝑜𝑟𝑒 + 𝐺↓𝑗𝑎𝑓𝑡𝑒𝑟 )+ 𝐺↓𝑇𝑆𝑃 + 𝐺↓𝑟𝑒𝑚𝑎𝑖𝑛
=𝑐𝑦𝑐𝑙𝑒𝑙𝑒𝑛𝑔𝑡ℎ=𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 " 𝑇↓𝑇𝑆𝑃𝑒𝑛𝑑 − 𝑇↓𝑇𝑆𝑃𝑠 = 𝐺↓𝑇𝑆𝑃 " 𝑇↓𝐵𝐴𝑙𝑜𝑤 ≤ 𝑇↓𝑇𝑆𝑃𝑒𝑛𝑑 ≤ 𝑇↓𝐵𝐴𝑢𝑝 " 𝑇↓𝑇𝑆𝑃𝑠 =∑𝑗↑▒𝐺↓𝑗𝑏𝑒𝑓𝑜𝑟𝑒 " 𝐺↓𝑗𝑏𝑒𝑓𝑜𝑟𝑒 + 𝐺↓𝑗𝑎𝑓𝑡𝑒𝑟 =𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡 " 𝐺↓𝑗𝑏𝑒𝑓𝑜𝑟𝑒 ≥ 𝐺↓𝑚𝑖𝑛 𝑜𝑟 𝐺↓𝑗𝑏𝑒𝑓𝑜𝑟𝑒 =0
" 𝐺↓𝑗𝑎𝑓𝑡𝑒𝑟 ≥ 𝐺↓𝑚𝑖𝑛 𝑜𝑟 𝐺↓𝑗𝑎𝑓𝑡𝑒𝑟 =0
" 𝐺↓𝑇𝑆𝑃 ≥ 𝐺↓𝑚𝑖𝑛 𝑜𝑟 𝐺↓𝑇𝑆𝑃 =0
" 𝐺↓𝑟𝑒𝑚𝑎𝑖𝑛 ≥ 𝐺↓𝑚𝑖𝑛 𝑜𝑟 𝐺↓𝑟𝑒𝑚𝑎𝑖𝑛 =0 " Choice variables: G1before, G2before, G3before, and TTSPend.
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Evaluations
! Compare three scenarios " No TSP " Conventional TSP " TSPCV
! MOEs " Bus delay " Person delay of all motorists
! Test network " Emmet St. and Barracks Rd., Charlottesville, VA " Field collected data (volume, signal timing)
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Evaluations
! Analytical test " VBA in excel " Theoretical benefit without randomness and uncertainties " Evaluated all TSP possibilities, less biased
! Simulation test " Randomness and uncertainties " VISSIM " Developed COM Interface
• Access CV technology information • Make changes to signal phasing in real time • Assign desired speed to the bus
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Single Bus TSP Evaluation
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50
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200
250 1 6 11
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46
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Bu
s Tr
avel
Tim
e (S
ec)
TSP Activation Time (Sec)
Bus Travel Time
w/o TSP
with TSP
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Single Bus TSP Evaluation
Analytical Delay Comparison for One-Bus Scenario
v/c ratio NTSP CTSP TSPCV N/TSPCV C/TSPCV
Bus Delay (Sec)
0.5 57.7 50.3 5.3 -90.8% -89.5%
0.7 57.7 50.3 5.3 -90.8% -89.5%
0.9 57.7 50.4 5.9 -89.7% -88.3%
1.0 57.7 51.1 27.1 -53.0% -46.8%
Delay per person (Sec)
0.5 46.8 46.8 44.1 -5.6% -5.6%
0.7 46.8 46.8 44.1 -5.6% -5.6%
0.9 49.5 49.5 46.7 -5.6% -5.6%
1.0 51.1 51.1 48.3 -5.6% -5.5%
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Single Bus TSP Evaluation
MOE v/c ratio NTSP CTSP TSPCV N/TSPCV C/TSPCV
Bus Delay (Sec)
0.5 39.1 27.5 5.6 -85.7% -79.7%
0.7 40.6 29.2 4.8 -88.3% -83.7%
0.9 45.4 36.3 18.1 -60.1% -50.0%
1.0 48.7 34.0 30.9 -36.5% -9.2%
Delay per person (Sec)
0.5 36.1 33.0 30.9 -14.3% -6.2%
0.7 37.6 34.7 33.2 -11.6% -4.3%
0.9 42.8 39.2 40.3 -5.9% 2.6%
1.0 52.0 44.5 45.7 -12.0% 2.8%
STDDEV (sec) All 31 32 26 -16.1% -18.8%
Simulation Delay Comparison for One-Bus Scenario
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Measuring Transit Performances
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Motivations & Objective
! In assessing or redesigning transit system, performance measures such as passenger waiting time at bus stop, and passenger origin-destination information are key
! Small to medium size cities redesign transit system
(e.g., location of bus stops and even bus routes) without proper data
! To develop and evaluate low cost technology based solution (Bluetooth or WiFi + Raspberry Pi)
Bluetooth, WiFi, and MAC Address
Bluetooth Readers for Link Travel Time Estimation
Field Data Collection (Device: Bluetooth/WiFi + Raspberry Pi)
Bluetooth & WiFi Readers: Hardware
! Raspberry Pi 2 Model B (current version 3) ! Bluetooth Adapter ! WiFi Adapter ! 5V/2A Portable Battery
Bluetooth & WiFi Readers: Software
! Raspbian Jessie Lite Operating System ! TShark ! Python Code
Comparison of Unique ID Samples
! Bluetooth/WiFi should be “on” to be detected
! Bluetooth IDs are about 1% of WiFi ! Why? iOS & Bluetooth “off”
Bluetooth WiFi
Chemistry Building 15 1,789
Garrett Hall 14 1,696
Based on MAC Address collected during an hour on Monday, March 21, 2016
Technology Verification with Known Device
Bus # Time on Bus
–Field Verification
Time off Bus – Field Verification
Estimated Trip
Duration (sec)
Time on Bus – Reader
Verification
Time off Bus – Reader
Verification
Duration of Trip (sec)
1 17:34 17:36 - - - -
2 17:51 17:54 120-240 17:51:39 17:54:29 170
3 18:03 18:06 120-240 18:03:41 18:06:54 193
4 18:25 18:26 - - - -
Average 180 Average 181.5
Passenger Bus Stop Waiting Time
Bus #
Chemistry Building (#65) Garrett Hall (#63)
MAC Detected
Bus Arrival Time
MAC Disappeared
Bus Stop Waiting Time MAC
Detected Bus Departure
Time
1 17:32:39 17:34 17:33:58 0:01:19 17:36:53 17:36
2
17:49:09
17:51
17:51:13 0:02:04 17:54:10
17:54
17:28:18 17:51:11 0:22:53* 17:53:14
17:49:09 17:51:21 0:02:12 17:54:10
17:51:11 17:51:35 0:00:24 17:53:53
17:50:24 17:51:27 0:01:03 17:53:16
3
18:02:56
18:03
18:03:14 0:00:18 18:06:15
18:06 17:59:43 18:03:14 0:03:31 18:06:12
17:59:07 18:03:49 0:04:42 18:06:06
18:02:56 18:03:30 0:00:34 18:06:15
4 18:25:17 18:25 18:25:31 0:00:14 18:26:47 18:26
Sample Rate & Passenger OD Information
Bus #
Chemistry Building Garrett Hall Origin Destination
MAC Detected Bus
Arrival Time
# pax onboard
# Devices Detected
MAC Detected
Bus Departure
Time
Travel Time (sec)
Sample Rate
1 17:32:39 17:34 2 1 17:36:53 17:36 254 50%
2
17:49:09
17:51 9
4
17:54:10
17:54
301
44%
17:28:18 17:53:14 1496*
17:49:09 17:54:10 301
17:51:11 17:53:53 162
17:50:24 17:53:16 172
3
18:02:56
18:03 16 4
18:06:15
17:06
199
25% 17:59:43 18:06:12 389
17:59:07 18:06:06 419
18:02:56 18:06:15 199
4 18:25:17 18:25 4 1 18:26:47 17:26 90 25%
Low Cost Solution
! Dedicated Short Range Communication (DSRC) " Roadside Unit: $2-3K " Onboard Unit: $2K " Latency: 100 ms
! LoRa Wide Area Network (LoRaWan) " LoRa Gateway: $1-2K " LoRa end node: ~$50 " Low power and long range " Each Gateway supports up to 20K IoT devices " Latency: 1-2 seconds
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LoRa Technology
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Collaborators: Samy El-Tawab (JMU)
Jia Hu (Tongji U) Saerona Choi (KTSA)
John Whittier & Seunghan (Francis) Ryu (UVA)