t TNO Human Factors Driving behaviour effects of the Chauffeur Assistant Jeroen Hogema

t 16 December Overview Background Method TNO driving simulator Simulating the CA Experimental design Results Conclusions consequences for traffic simulation model

t 16 December Dutch Evaluation of the Chauffeur Assistant (DECA) Chauffeur Assistant Adaptive Cruise Control Lane Keeping System Follow-up of Lane Departure Warning Assistant FOT Transport Research Centre (TRC) Ministry of Transport, Public Works, and Water Management

t 16 December Chauffeur Assistant: Questions Individual driver level driving behaviour workload acceptance traffic flow level traffic performance safety indicators

t 16 December DECA DRIVING SIMULATO R behaviour TNO MIXIC interpretation report MIXIC simulations TR C workload acceptance driver CA

t 16 December Method – Driving simulator visual audio steering force motion

t 16 December Method – Driving simulator DAF 95XF lorry Mass kg (fully loaded) Maximum engine power: 350 kW Parameter set from DAF trucks

t 16 December Method – Simulating the CA Adaptive Cruise Control DC specifications Distance law for car-following Dref = * v Dref = ACC's intended following distance (m) v=current speed (m/s) Braking: max. -3 m/s 2

t 16 December Method – Simulating the CA ACC controller structure from earlier work parameters from recent ACC work by TNO Automotive

t 16 December Method – Simulating the CA ACC reference scenarios approaching braking lead car accelerating lead car cut-in Dynamic behaviour of reference model driving simulator CA MIXIC CA

t 16 December Method – Simulating the CA LKS noise added to obtain realistic servo performance SDLP about 10 cm

t 16 December Method - Experimental design (1) with vs without CA traffic volume low (3400/u) high (6000/u) 3-lane motorway, 3.5 m wide lanes ACC headway D ref = t k * v t k = 1.0 – 1.3 – 1.6 s 1 preferred setting selected by each driver prior to experiment

t 16 December Method - Experimental design (2) Scenarios car-following (overtaking possible) braking lead car 3 m/s 2 4 m/s 2 Subjects 18, professional truck drivers at least 5 years 'groot rijbewijs' age between paid for their participation

t 16 December Human Machine Interface driver turns CA turns on/off switches brake pedal driver sets ACC speed buzzer at maximum braking display ACC set speed on speedometer symbol: headway control or speed control

t 16 December Results – preferred CA time headway 1.0 s 1 x 1.3 s 8 x 1.6 s 9 x Total18 x

t 16 December Results – SD lateral position effect of CA

t 16 December Results – Time to Line Crossing effect of CA

t 16 December Results – close following effect of CA

t 16 December Results – lane change frequency effect of CA on edge of marginal significance [p<.11]

t 16 December Braking lead car: lane change response lane change reaction of subject Fewer lane changes with CA

t 16 December Braking lead car: braking response braking reaction of subject lower deceleration levels with CA

t 16 December Results – mental effort Rating Scale of Mental Effort effect of CA

t 16 December Acceptance (1) MeanStd.Dev. useful-useless pleasant-unpleasant good-bad nice-annoying effective-superfluous likeable-irritating assisting-worthless desirable-undesirable raising alertness-sleep inducing scales:

t 16 December Acceptance (2) Underlying variables USEFULNESS: SATISFACTION:

t 16 December Summary of results (1) With Chauffeur Assistant… reduced SD of lateral position higher Time to Line Crossings less short time headways reduced Mental Effort (fewer changes with CA?)

t 16 December Summary of results (2) Acceptance: positive except “sleep-inducing” Lane changes fewer changes with CA? Braking lead car fewer lane changes with CA less critical behaviour with CA (maximum deceleration, minimum TTC) No effects on: mean, s.d. speed lane use (% right lane) mean lateral position mean time headway

t 16 December Chauffeur Assistant in MIXIC drivervehicle CA

t 16 December Chauffeur Assistant in MIXIC DRIVER VEHICLE CA car following free driving lane change model LATERAL LONGITUDINAL settings transitions CA

t 16 December MIXIC driver model Driver – CA CA settings CA reference speed = driver’s intended speed CA reference headway: 50% 1.3 s; 50% 1.6 s CA off when: CA is braking hard AND driver would brake harder starting lane-change manoeuvre CA on when: “possible”

t 16 December MIXIC driver model Lane change behaviour small effects nature of effects unknown tactical level: avoid getting 'stuck' in car-following in a 'slow' lane driver-state related: reduced alertness, complacency, less 'active' driving => no changes in lane change model

t 16 December Conclusions Behaviour Workload effects in line with ACC or LKS research Acceptance } Chauffeur Assistant – ACC + LKS: contribution of ACC and LKS unknown Minor modifications to MIXIC->driver->ACC model