CICAS Coordination Meeting September 28th, 2004 Virginia Update

Research Questions Addressed To Date Is there a difference in brake profiles for distracted vs. willful vs. baseline drivers? Is there a difference in brake profiles for distracted vs. willful vs. baseline drivers? What’s a too early warning? What’s a too early warning? What’s a too late warning? What’s a too late warning? What timing aspects of the algorithm will minimize false alarms and misses? What timing aspects of the algorithm will minimize false alarms and misses? What is the effect of warning mode on driver response? What is the effect of warning mode on driver response? How many detection points are needed to have an effective algorithm? How many detection points are needed to have an effective algorithm? What functional requirements are known? What functional requirements are known?

Is there a difference in brake profiles for distracted vs. willful vs. baseline drivers?

Braking Profiles Algorithms can be built based on detection of violation-likely groups: Algorithms can be built based on detection of violation-likely groups: –Drivers stop differently depending on their intentions and level of distraction Distracted drivers stop harder than others Distracted drivers stop harder than others Distracted drivers are less likely to stop Distracted drivers are less likely to stop Distracted drivers are more likely to violate Distracted drivers are more likely to violate Willful drivers tend to speed Willful drivers tend to speed

What’s a too early warning? A warning that is issued to a driver that would have stopped without any intervention A warning that is issued to a driver that would have stopped without any intervention –Creates annoyance –Decreases user trust Too early was determined during first three intersection studies Too early was determined during first three intersection studies

Too Early Distribution The figure depicts the distance from the intersection at which baseline drivers initiated braking when the signal change occurs at 185’ An algorithm that initiates a warning prior to reaching 135’ would create false alarms Number of Drivers (out of 28) Distance to Intersection (ft)

What’s a too late warning? A warning that is issued to a driver that would benefit, but with timing such that insufficient distance remains for the driver to perceive, react, and stop prior to entering the intersection. A warning that is issued to a driver that would benefit, but with timing such that insufficient distance remains for the driver to perceive, react, and stop prior to entering the intersection. –Decreases safety benefit of system –Decreases user trust

Ideal Case – Classification Clearance

Real Case – Classification Interference

Maximizing Curve Separation (Methods to Minimize Misses and False Alarms) Take advantage of the “all red” phase and the time it takes for opposing vehicles to get into the collision zone to allow vehicles to pass through without warning (time) Take advantage of the “all red” phase and the time it takes for opposing vehicles to get into the collision zone to allow vehicles to pass through without warning (time) Take advantage of the intersection’s buffer zone, the area beyond the stop bar but prior to significant collision risk (space) Take advantage of the intersection’s buffer zone, the area beyond the stop bar but prior to significant collision risk (space) Design warnings that minimize reaction time and maximize deceleration by conveying necessary urgency Design warnings that minimize reaction time and maximize deceleration by conveying necessary urgency

“Normal” Brake Initiation Normal Approach No Warning or Timely Warning

Too Late Warning Algorithm Trip Reaction Time “Normal” Brake Initiation

Allowing the Violation Preventing the Crash

Making Use of Pre-Collision Zones of the Intersection Compliant ZoneViolation ZoneIntrusion ZoneCollision Zone

Warning Activation Preventing the Collision

Maximize Warning Effectiveness DII/DVI research to date has demonstrated the importance of countermeasure design. DII/DVI research to date has demonstrated the importance of countermeasure design. –Prototype warnings were evaluated for Urgency, Distinguishability, and Appropriateness in the lab Evaluators preferred icon auditory warnings over descriptive (i.e. buzzer vs. “Stop”) Evaluators preferred icon auditory warnings over descriptive (i.e. buzzer vs. “Stop”) However, experimentation showed clear advantages for the word “Stop” However, experimentation showed clear advantages for the word “Stop”

Maximize Warning Effectiveness

Comparison of Auditory Alerts Group Percent Who Stop Before Collision Zone Avg. Maximum Deceleration (g) Avg. Reaction Time (sec) CAMP Warning 64% “Stop” 81%

Effectiveness of Visual Display –High Heads-Down Visual DVI was ineffective The display was perceived by less than 5 percent of the participants The display was perceived by less than 5 percent of the participants Evaluation of DVIs is now focused on auditory and haptic warning modes Evaluation of DVIs is now focused on auditory and haptic warning modes

How many detection points are needed to have an effective algorithm? Single-Point detection of speed does not result in reliable warning decisions Single-Point detection of speed does not result in reliable warning decisions –Improved reliability would consistently result in too late warnings Continuous detection is the most adaptive to any algorithm type and produces the best theoretical performance Continuous detection is the most adaptive to any algorithm type and produces the best theoretical performance Multi-point alternatives are being tested Multi-point alternatives are being tested

Simulation of Single Point vs. Continuous Detection Missed Violations Speed determined at given distance from intersection for violations that occurred Speed determined at given distance from intersection for violations that occurred Single point detection would not have worked for most of the drivers who violated Single point detection would not have worked for most of the drivers who violated With continuous detection, three violating drivers would not have been detected; however, none of these drivers would have been in the crash zone. With continuous detection, three violating drivers would not have been detected; however, none of these drivers would have been in the crash zone.

What functional requirements are known? Detuning tests run to date Detuning tests run to date –Sensors Acceleration Acceleration Velocity Velocity –Positioning Lateral Position Lateral Position Longitudinal Position Longitudinal Position

Sensor: Velocity Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required to stop by the stop bar

Sensor: Accelerometer Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required to stop by the stop bar

Positioning: Lateral Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required to stop by the stop bar

D = 125 ft d = ft Positioning: Lateral Assumes a 12 foot lane width Assumes a 12 foot lane width Would also apply to curved road geometry Would also apply to curved road geometry

Positioning: Lateral Lane Position: Correct vs. Incorrect 25 mph Correct 25 mph Incorrect 70 mph Correct 70 mph Incorrect -5 m m m m m m m0606

Positioning: Longitudinal Normalized Deceleration: At DVI onset, the average deceleration in g’s that would be required to stop by the stop bar

Project Plans Completing studies to answer the following questions Completing studies to answer the following questions –What is the optimal timing for collision warning? –What is the optimized braking profile for a haptic warning system? –What are the remaining functional requirements and specifications of an ICA system? –What DII and DVI will result in optimal driver response? –What technologies show the most promise for the feasible architectures? –What ICA architectures are feasible for meeting the requirements and specifications?

What is the optimal timing for collision warning? Need to continue to systematically determine the ‘too late’ points for various DIIs and DVIs Need to continue to systematically determine the ‘too late’ points for various DIIs and DVIs –A goal of zero misses is being used –Driver acceptance is being considered ‘Too late’ thresholds are being contrasted with known ‘too early’ thresholds, to determine the potential for nuisance alarms ‘Too late’ thresholds are being contrasted with known ‘too early’ thresholds, to determine the potential for nuisance alarms

What is the optimized braking profile for a haptic warning system? It is known that severely distracted drivers can have perception reaction times as long as 4 sec, which would make any traditional warning ineffective It is known that severely distracted drivers can have perception reaction times as long as 4 sec, which would make any traditional warning ineffective A brake assist or full brake system is seen as a possible means of aiding these drivers, since reaction time is eliminated A brake assist or full brake system is seen as a possible means of aiding these drivers, since reaction time is eliminated Three issues are being resolved: Three issues are being resolved: –When should the system be activated? –How long should the system remain active? –How much braking authority should be used?

Brake Assist Example

Savings of 50ft at 35mph

What are the remaining functional requirements and specifications of an ICA system? Need to test between 1 m and 2.5 m on lateral position. Need to test between 1 m and 2.5 m on lateral position. Need to determine effects of various communication system update rates Need to determine effects of various communication system update rates

What DII and DVI will result in optimal driver response? Will continue to conduct evaluation of brake assist and full brake options. Will continue to conduct evaluation of brake assist and full brake options. Will continue to test auditory and haptic options. Will continue to test auditory and haptic options.

What technologies show the most promise for the feasible architectures? VTTI will continue to determine technologies that meet the minimal functional requirements VTTI will continue to determine technologies that meet the minimal functional requirements –Controller –Positioning –Sensors –Driver Interface –Communications –Computations

Controller Technologies No single interface standard available No single interface standard available Available timing information not accurate enough Available timing information not accurate enough –Ex.: Eagle controllers report timings to whole seconds Overhead from 10Hz polling may overload controller Overhead from 10Hz polling may overload controller May need to mandate standards for data format/availability May need to mandate standards for data format/availability New Advanced Traffic Controllers (ATCs) may address some of these issues New Advanced Traffic Controllers (ATCs) may address some of these issues

Positioning Technologies Infrastructure based Infrastructure based –Radar: costly to cover all lanes –RFID: may require multiple readers per approach Vehicle based Vehicle based –GPS with INS: high cost to get high accuracy and update rate –RFID in conjunction with odometer: high accuracy at one distance, then decrement remaining distance using odometer

Sensor Technologies Infrastructure Infrastructure –Radar: velocity and deceleration Vehicle velocity Vehicle velocity –GPS with INS: velocity –Velocity from vehicle network Vehicle deceleration Vehicle deceleration –Accelerometer to sense braking –Mechanical sensor on brake pedal

Driver Interface Technologies Infrastructure Infrastructure –Strobes –VMS sign –Intelligent rumble strips Vehicle Vehicle –Auditory: tones or voice warning –Haptic: Soft braking (pulses), seat shaker, brake assist, or full braking

Communications Technologies Must be generic to support multiple interfaces Must be generic to support multiple interfaces Bi-directional link depending on architecture Bi-directional link depending on architecture DSRC current best choice DSRC current best choice –Not yet available off-the-shelf –Security issues –Styling issues –Currently simulating with a hardware and software

Computations Technologies Infrastructure Infrastructure –On board signal controller –Custom DSP or hybrid microcontroller Must talk to infrastructure components Must talk to infrastructure components –radar –RFID –DSRC –DII Easily modified to allow algorithm changes Easily modified to allow algorithm changes

Computations Technologies Vehicle Vehicle –Custom DSP or hybrid microcontroller Must talk to all necessary data sources Must talk to all necessary data sources –vehicle network –DSRC –GPS w/INS –RFID –DVI Easily modified to allow algorithm changes Easily modified to allow algorithm changes

What ICA architectures are feasible for meeting the requirements and specifications? VTTI will continue to evaluate the available technologies as suitable to several architectures VTTI will continue to evaluate the available technologies as suitable to several architectures –Infrastructure only –Mostly infrastructure based with receiver and DVI in vehicle –Mostly vehicle based with transmitter in infrastructure (provides stop bar location and signal phase/timing) –Totally vehicle based with map in vehicle For stop signed intersections For stop signed intersections

Architecture Example 1. RFID tag reader and in-vehicle warning RFID transmits distance to intersection to vehicle Odometer updates distance to intersection DVI in vehicle presents warning and driver stops DSRC transmits signal phase and timing to vehicle

Radar determines vehicle speed and distance Architecture Example 2. Infrastructure radar and DII Radar determines vehicle speed and distance Algorithm calculates violation DII in infrastructure presents warning and driver stops DSRC violation warning also transmitted to properly equipped vehicles

Architecture Example 3. In-vehicle positioning system and in-vehicle warning In-vehicle map query for stop bar location Distance and speed calculated to check for violation DVI in vehicle presents warning and driver stops STOP

Additional Pre-FOT Testing Next steps toward an FOT Next steps toward an FOT –Passive evaluation of both infrastructure based and cooperative ICA systems When was the warning issued? When was the warning issued? How many false alarms and misses occurred? How many false alarms and misses occurred? What would have been the resulting driver and traffic consequences? What would have been the resulting driver and traffic consequences?

Additional Pre-FOT Testing Data from the passive evaluation will also validate the functional specifications for a cooperative system Data from the passive evaluation will also validate the functional specifications for a cooperative system Then we will have enough data to activate the DII warning at a limited number of intersections and continue to closely monitor traffic Then we will have enough data to activate the DII warning at a limited number of intersections and continue to closely monitor traffic –Do naturalistic on-road experimentation for the cooperative system with instrumented vehicle Look for unintended consequences Look for unintended consequences Make the final assessment of acceptability Make the final assessment of acceptability