Förberedande provning och verifiering av alkosensorer inför fältprov

Rapporten är framtagen med ekonomiska bidrag från Trafikverkets Skyltfond. Ståndpunkter och slutsatser i rapporten reflekterar författaren och överensstämmer inte med nödvändighet med Trafikverkets ståndpunkter och slutsatser inom rapportens ämnesområden. Redan 2005 påbörjades KAIA-projektet (akronym för “förar-och fordonskompatibel alkoholsensor med inbyggd absolutmätning”), med målsättningen att på sikt kunna utveckla nya användarvänliga system för mätning av alkoholhalten i utandningsluften, där föraren enbart gör en riktad utandning mot alkoholsensorn. En annan fördel är att mätprincipen baserar sig på IR-teknik och då bortfaller behovet av kalibrering, som i konventionella sensorer behöver göras årligen. Den här långsiktiga forsknings- och utvecklingssatsningen har huvudsakligen genomförts av Autoliv, Hök Instrument och SenseAir med stöd från IVSS, Vinnova, Trafikverket, FFI och ACTS/NHTSA (National Highway Traffic Safety Administration - US). Skyltfondsprojektet; ”Förberedande provning och verifiering av alkosensorer inför fältprov” är en liten men betydelsefull del av den här satsningen. Flera väsentliga och positiva resultat har kommit fram. Inverkan från främmande ämnen undersöktes genom mätningar och teoretiska studier. Resultaten visar att vi med god marginal klarar de ämnen som tas upp i CENELEC-standarden EN50436-1. De inledande försöken med berusade passagerare visar att deras närvaro i fordonskupén har minimal, om ens någon, effekt på mätprestanda hos alkosensorsystemet. Mätalgoritmen har optimerats genom att vikta olika mätsamples och på så sätt har vi avsevärt kunnat reducera det sammanvägda stokastiska bruset med bättre mätnoggrannhet som följd. Sensorns uppstartstid, speciellt vid låga temperaturer, har förkortats delvis med hjälp av en avancerad algoritm

Development and Evaluation of Algorithms for Breath Alcohol Screening

Breath alcohol screening is important for traffic safety, access control and other areas of health promotion. A family of sensor devices useful for these purposes is being developed and evaluated. This paper is focusing on algorithms for the determination of breath alcohol concentration in diluted breath samples using carbon dioxide to compensate for the dilution. The examined algorithms make use of signal averaging, weighting and personalization to reduce estimation errors. Evaluation has been performed by using data from a previously conducted human study. It is concluded that these features in combination will significantly reduce the random error compared to the signal averaging algorithm taken alone

Passive in-vehicle driver breath alcohol detection using advanced sensor signal acquisition and fusion

Objective: The research objective of the present investigation is to demonstrate the present status of passive in-vehicle driver breath alcohol detection and highlight the necessary conditions for large-scale implementation of such a system. Completely passive detection has remained a challenge mainly because of the requirements on signal resolution combined with the constraints of vehicle integration. The work is part of the Driver Alcohol Detection System for Safety (DADSS) program aiming at massive deployment of alcohol sensing systems that could potentially save thousands of American lives annually. Method: The work reported here builds on earlier investigations, in which it has been shown that detection of alcohol vapor in the proximity of a human subject may be traced to that subject by means of simultaneous recording of carbon dioxide (CO2) at the same location. Sensors based on infrared spectroscopy were developed to detect and quantify low concentrations of alcohol and CO2. In the present investigation, alcohol and CO2 were recorded at various locations in a vehicle cabin while human subjects were performing normal in-step procedures and driving preparations. A video camera directed to the driver position was recording images of the driver's upper body parts, including the face, and the images were analyzed with respect to features of significance to the breathing behavior and breath detection, such as mouth opening and head direction. Results: Improvement of the sensor system with respect to signal resolution including algorithm and software development, and fusion of the sensor and camera signals was successfully implemented and tested before starting the human study. In addition, experimental tests and simulations were performed with the purpose of connecting human subject data with repeatable experimental conditions. The results include occurrence statistics of detected breaths by signal peaks of CO2 and alcohol. From the statistical data, the accuracy of breath alcohol estimation and timing related to initial driver routines (door opening, taking a seat, door closure, buckling up, etc.) can be estimated.The investigation confirmed the feasibility of passive driver breath alcohol detection using our present system. Trade-offs between timing and sensor signal resolution requirements will become critical. Further improvement of sensor resolution and system ruggedness is required before the results can be industrialized. Conclusions: It is concluded that a further important step toward completely passive detection of driver breath alcohol has been taken. If required, the sniffer function with alcohol detection capability can be combined with a subsequent highly accurate breath test to confirm the driver's legal status using the same sensor device. The study is relevant to crash avoidance, in particular driver monitoring systems and driver-vehicle interface design

Assessment of the breath alcohol concentration in emergency care patients with different level of consciousness

Background Many patients seeking emergency care are under the influence of alcohol, which in many cases implies a differential diagnostic problem. For this reason early objective alcohol screening is of importance not to falsely assign the medical condition to intake of alcohol and thus secure a correct medical assessment. Objective At two emergency departments, demonstrate the feasibility of accurate breath alcohol testing in emergency patients with different levels of cooperation. Method Assessment of the correlation and ratio between the venous blood alcohol concentration (BAC) and the breath alcohol concentration (BrAC) measured in adult emergency care patients. The BrAC was measured with a breathalyzer prototype based on infrared spectroscopy, which uses the partial pressure of carbon dioxide (pCO2) in the exhaled air as a quality indicator. Result Eighty-eight patients enrolled (mean 45 years, 53 men, 35 women) performed 201 breath tests in total. For 51% of the patients intoxication from alcohol or tablets was considered to be the main reason for seeking medical care. Twenty-seven percent of the patients were found to have a BAC of <0.04 mg/g. With use of a common conversion factor of 2100:1 between BAC and BrAC an increased agreement with BAC was found when the level of pCO2 was used to estimate the end-expiratory BrAC (underestimation of 6%, r = 0.94), as compared to the BrAC measured in the expired breath (underestimation of 26%, r = 0.94). Performance of a forced or a non-forced expiration was not found to have a significant effect (p = 0.09) on the bias between the BAC and the BrAC estimated with use of the level of CO2. A variation corresponding to a BAC of 0.3 mg/g was found between two sequential breath tests, which is not considered to be of clinical significance. Conclusion With use of the expired pCO2 as a quality marker the BrAC can be reliably assessed in emergency care patients regardless of their cooperation, and type and length of the expiration

NORD-pie - Piezoelectric micro-electromechanical systems for Nordic industry

NORD-pie will form the basis for a qualified piezo-MEMS service including feasibility studies, design and production. The project will demonstrate the availability of small scale and high quality industrial fabrication of piezoelectric MEMS devices in the Nordic countries. NORD-pie aims to provide piezoelectric thin film technology to Nordic industr