Intelligent speed control and effects on driving behaviour
01 Jan 1999-pp 31
TL;DR: In this paper, an in-vehicle system called Intelligent Cruise Control (ICC) is used to regulate a vehicle's speed and maintain a proper following distance behind a lead vehicle.
Abstract: Supporting the driver in conducting his nowadays demanding task is a promising means to get the maximum out of the road system with respect to both efficiency and safety. With respect to safety, speed management is a main issue. Police enforcement of speeding is one approach, preventing high speeds another. Intelligent Cruise Control (ICC) Systems may enable this by operating at an externally induced reference speed limit. ICC is an in-vehicle system that automatically regulates a vehicle's speed and is capable of maintaining a proper following distance behind a lead vehicle. ICCs so far can realise a moderate level of deceleration: in situations that require higher the driver must take over control. Some kind of short-range communication with the road side offers the option to obtain in-car preview information about relevant conditions on the road ahead, including prevailing speed limits). Some driving simulator studies were conducted to assess the effects of ICC on driving behaviour for both informative and intervening ICC systems. The results reveal that ICC yields more consistent longitudinal control: in car-following situations, there is less variation in headway and in speed. Only intervening systems result in a speed reduction on motorway sections with a special speed limit, but at a cost of somewhat higher speeds at non-controlled sections. In critical scenarios (approaching a sudden traffic queue) where ICC could not cope with completely and the driver had to take over control, a somewhat later braking reaction of the driver was found. Also within the European project MASTER (MAnaging Speeds of Traffic on European Roads) the testing of the testing of (dynamic) speed limiters in a simulator study resulted in a reduced speed, speed variance and speed at hazardous locations. However, the speed limiters also had secondary effects that could compromise safety, viz. a higher incidence of short headways, delayed braking and a higher incidence of collisions. A field-trial with an in-vehicle dynamic speed limiter in three countries (Sweden, The Netherlands, and Spain) revealed that the speed limiter significantly reduced speed on 30-70 km/h roads, but not on 80-90 km/h roads and motorways (mainly due to heavy traffic conditions). In conclusion, automatic speed limiting by an in-car device seems most promising within built-up areas. Some concern about behavioural adaptation mechanisms may apply.
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01 Jan 2004
TL;DR: It is concluded that the most promising sustainable and safety-improving approach in the future is the use of intelligent electronic systems such as ISA combined and integrated in the whole design of the road traffic system consisting of both the geometric design and dynamic traffic management.
Abstract: The PROSPER (Project for Research On Speed adaptation Policies on European Roads) project, funded by the European Commission within the 5th framework program, was initiated to find answers concerning efficiency, public support, and implementation of road speed management methods, particularly Intelligent Speed Adaptation (ISA) in Europe. A part of the PROSPER project was to examine the effect of Human Machine Interaction (HMI) design for ISA could on driving behaviour and acceptance. Therefore, sixty-four experienced drivers participated in two experiments (32 each), in a moving-base research driving simulator. During the simulated runs with ISA, the speed limit was communicated through the ISA system. The ISA system consisted of an indication of the speed limit on the speedometer, and a gas pedal that could either be used as a haptic or tactile pedal, or as a dead throttle. Two versions of the haptic gas pedal were examined in experiment (a): a low-force ISA (easy to overrule, informative in nature) and a high-force ISA (stronger counter force, more compulsory in nature). Two other configurations were tested in experiment (b): a tactile pedal (a vibration on the gas pedal, informative in nature) and a dead throttle (completely restraining the driver from exceeding the speed limit). It was hypothesised that the closer to an informative type of ISA, the higher acceptance and the smaller the effects on driving behaviour would be. This hypothesis appeared to be valid, although for both driving behaviour and acceptance, not all four HMIs could be ranked unambiguously on the scale from no ISA to full ISA. In sharp curves, drivers appeared to chose a driving speed below the speed limit, irrespective of ISA. The specific road environment scenarios that were inserted to examine presupposed compensatory behaviour for experienced delay, indicated no signs of compensatory driving behaviour. Finally, it is concluded that the most promising sustainable and safety-improving approach in the future is the use of intelligent electronic systems such as ISA combined and integrated in the whole design of the road traffic system consisting of both the geometric design and dynamic traffic management.
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Cites background from "Intelligent speed control and effec..."
...In the real world road environment it is plausible that ISA is only activated on certain road sections, thus allowing for compensatory behaviour on non-ISA sections (see for example van der Horst & Hogema, 1999)....
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