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DSRC Accident Warning System at Intersection
Team Pishro-Nik & Ni Richa Prasad ● Raza Kanjee ● Hui Zhu ● Thai Nguyen Professor Prishro-Nik Advisor, Assistant Professor, ECE Professor Ni Advisor, Assistant Professor, CEE
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Content Introduction The Design Deliverables System Block Diagram
MDR Specifications Spec 1 – Latency Calculations Spec 2 – Transceiver Spec 3 – Traffic Light Power Specifications Product Cost PDR I Questions Summary
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Annual fatality rate > 40,000 for more than 30 years
Introduction © PReVENT Straight Crossing: 203,000 PAR crashes 200,000 non-PAR crashes Injury, casualty, traffic delay, economic loss These situations at intersections represent about: 65% of injury accidents 70% of fatal accidents Annual fatality rate > 40,000 for more than 30 years
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The Design VII DSRC Vehicle Infrastructure Integration Traffic
Dedicated Short Range Communication 5.9 GHz Frequency Band Allocated for VII IEEE Standard: p Tutor Routing Entertainment Safety Weather Traffic Management Path Suggestion Speed Suggestion Pedestrian Warning © PReVENT
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Deliverables OBU sends back speed and location 1
RSU is warned of traffic light turning red 3 RSU calculates whether red car will run red light 2 Message sent to red car asking for speed and position If yes, blue car warned 4 GOALS Real-life demonstration Running light warning only Simulation of two cars – one moving, one at light Technical Documentation © PReVENT © PReVENT
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System Block Diagram
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System Block Diagram Not Complete Complete
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MDR Specifications Distance for Vehicle Warning Latency Calculations
AIM Distance for Vehicle Warning Latency Calculations Determination of car running red light Background for Accident Conditions Wireless connection between Bridge & AP Transceiver Two-way communication between laptops Data communicated = random && != GPS Hardware Simulation of traffic light Traffic Light Display of changing conditions on Bar LED Changing conditions recognized by laptop
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Spec 1 – Latency Calculations
MODEL SCENARIO Aim: Speeding Car – Emergency Braking Other cars warned; caution Car approaching intersection Car waiting at intersection Signalized Intersection, Straight Crossing Path (SI/SCP) If red car running light; both cars warned
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Spec 1 - Latency Calculations
BACKGROUND OF ACCIDENTS SI/SCP Crash Occurrence due to Pavement Condition SI/SCP Crash Occurrence due to Ambient Weather Condition SI/SCP Crash Occurrence due to Ambient Light Condition Rain 12% Dark, Unlighted 3% Dawn/Dusk 3% Snowy or Icy 2% Snow/Sleet 12% Dark, Lighted 22% Dry 79% No Adverse Weather 66% Daylight 72% Wet Pavement 19% Vision Obstructed 4.3% Vehicle Defect 1.9% Other 5.9% Driver Inattention 36.4% SI/SCP Crash Occurrence Driver Intoxication 12.9% Failed to Obey Signal 23.2% Tried to beat Signal 16.2% Travel Velocity (mph)
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Spec 1 – Latency Calculations
WARNING SYSTEM Factors Travel Speed Duration of amber light Level of braking Driver + machine delays Yes Start No Action Green Light? Yes No Yes Amber Light? Car can clear? No No No Yes Warning Red Light?
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Spec 1 - Latency Calculations
ROAD CALCULATIONS SV SV L Dilemma Zone Dcz Car B Dstop W Dcz = Clearance Zone Car can cross easily. Safe passing guaranteed Dilemma Zone Car can’t stop on time; can’t cross safely Dstop Distance required to come to a stop L = length of car W = width of intersection SV = Subject Vehicle Vsv = Velocity of Subject Vehicle a = deceleration rate trm + tmd = time delay due to human + machine Distance traveled in time left before red light Length of Car Width of Intersection Dcz = - - Distance for car to stop Human + Machine Delay Dstop = +
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Spec 1 - Latency Calculations
ROAD CALCULATIONS Dcz at different speeds with different amounts of time left before red light Dcz (m) Speed (kph)
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Spec 1 - Latency Calculations
ROAD CALCULATIONS ts = time to reach stop line tg = time for light to turn green Yes 30s to Red In Dcz? No No Calculate Dstop a = + or 0? Yes Yes No Action Dstop < Dloc No Calculate deceleration for v =0 at stop line Yes Comfortable range? Warning Time to reach stop line No Yes No ts < tg Dloc = distance from stop line
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Spec 1 - Latency Calculations
SYSTEM LATENCIES Traffic Light GPS R S U Almost Immediate Almost Immediate O B U Laptop Laptop Almost Immediate Almost Immediate Transceiver Transceiver 2400 baud = bps Longitude + Latitude + Speed Info = 12 bytes = 96 bits GPS Update = every 0.5s Size sent = 192 bps Available versus Used = 100:1 Human + Machine Delay = 2.0s Comfortable deceleration = 0 to 3 m/s 2 Status Messages: > 30s for red light Event Messages: < 30s for red light 1. Status Messages: RSU Laptop logs and saves data 2. Event Messages: RSU performs calculations 3. Status Messages: ALL calculations and data saved
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Spec 2 - Transceiver SPECIFICATIONS CONNECTIVITY
Airbornedirect Serial Bridge RS232 Serial Communication 802.11b/g Compliant 5 VDC External Supply Bridge 12 VDC 5 VDC 802.11g Ethernet Serial Access Point RSU OBU CONNECTIVITY
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Video Available on Request!
Spec 2 - Transceiver OUTPUT RSU OBU Video Available on Request!
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Microprocessor programmed with traffic light code
Spec 3 – Traffic Light SET UP Powered by USB Bar LED Traffic Light External Clock Power is on Microprocessor programmed with traffic light code Maxim chip – TTL to RS232 and vice versa Green to Warning – 60 s Warning to Yellow – 25 s Yellow to Red – 5 s Green to Red – 90 s JTAG programmer Indicator of data transfer Warning – 30 s
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Spec 3 – Traffic Light SPECIFICATIONS SV SV L Dilemma Zone Dcz Car B
Dstop W Dilemma Zone Subject Vehicle cannot cross safely before red light Subject Vehicle cannot stop safely at stop line tamber Aim Reduce Dilemma Zone 5 s Gazis et. Al: Posted Speed Limit
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Spec 3 – Traffic Light SCHEMATIC
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Spec 3 – Traffic Light OUTPUT Video Available on Request!
Warning sent 30s before light turns red Video Available on Request!
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Power Specifications Wireless Access Point – 12 VDC
Solution – 5V to 12V Booster Circuit USB Cable USB provides 5 VDC Powers: - GPS - Airbornedirect Bridge - Traffic Light Laptop – self-powered
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Product Cost
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PDR I Questions We can adjust the traffic light to prevent collisions. So why do we need the system? System too dynamic, unreliable. Predictability of traffic lights lost 2. Elevation on highway. How check if signal received by RSU is from OBU on same highway at which RSU is located? GPS provides altitude data If RSU altitude != OBU altitude; ignore signal 3. Losing connection with GPS. Solution? OBD II Implementation DGPS prevents full loss of connection with GPS 4. Urban setting – Accuracy and loss of connection with GPS OBD II Implementation Video cameras, laser sensors
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PDR I Questions 5. Plan for testing equipment?
Step 1 – Test in Lab Step 2 – Test in field Step 3 – Record all data in field Step 4 – Debug and test further in lab 6. Performance of project under different road and weather conditions? Specification 1 – Latency Calculations Majority of accidents – normal conditions 7. Theoretical Latency Measurements? Specification 1 – Latency Calculations 8. Vehicle not on road approaching intersection? Specify road width If collision predicted, should warn regardless
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Summary 1 Latency Calculations 2 Transceiver 3 Traffic Light CHECKLIST
Transceiver Communication Latency Calculations a. GPS-Laptop Communication b. GPS data reception by RSU Laptop 5. RSU Laptop Road Calculation Algorithm 1 Latency Calculations 2 Transceiver 3 Traffic Light MDR SPECIFICATIONS
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