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Author:Ahtiainen, Lauri
Title:Ajovalokehityksen vaikutus havaitsemiseen
The effect of automotive driving light development to traffic sign perception
Publication type:Master's thesis
Publication year:2014
Pages:75+1      Language:   fin
Department/School:Insinööritieteiden korkeakoulu
Main subject:Koneensuunnittelu   (K3001)
Supervisor:Juhala, Matti
Instructor:Sainio, Panu
Electronic version URL: http://urn.fi/URN:NBN:fi:aalto-201410212847
OEVS:
Electronic archive copy is available via Aalto Thesis Database.
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Location:P1 Ark Aalto  4298   | Archive
Keywords:driving light
beam pattern
traffic sign
perception
passanger car
glaring
ajovalo
valokuvio
henkilöauto
havaitseminen
liikennemerkki
Abstract (eng):This master's thesis concentrates on the possibility of reduced perception of traffic signs as a side effect of automotive headlight advancement.
The high luminous flux produced by high intensity discharge lamps, LEDs and alike have lead to a horizontally sharp cut off line in the low beam light pattern to prevent dazzling oncoming drivers.
As a side effect the sharp cut off line has caused re- duced ambient lighting outside the beam.

Traffic signs are typically installed considerably higher than the area illuminated by the passenger car low beams.
Typically the illumination of traffic sign comes from scattered light from the headlamp or low beam reflected from the road surface.

Low beams of the latest automotive illumination technologies such as high intensity discharge lights or LEDs have sharper cutoff line than previous technologies leading to lower ambient illumination, which lead to reduced traffic sign illumination.
At the same time the road on front of the vehicle has become brighter.

Perception of traffic lights was researched in a field study with both subjective tests and illumination measurements.
Modern automotive headlamps were represented in four test cars: two with LED headlamps, one with high intensity discharge headlamps and one with traditional halogen headlamps.

Based on the subjective tests and illumination measurements carried out during the field study the highest perception occurred with the traditional halogen headlamps.
When new traffic signs were used the differences between illumination technologies were small.
However, when worn traffic signs were used the perception errors became higher.
This was especially noticeable with the older persons, who fared better when the traffic signs were illuminated with traditional halogen beam.
Young test subjects succeed to perceive all traffic signs illuminated by all lighting technologies.

Based on the results of this thesis the current low beam pattern recommended by Economic Comission for Europe could possibly be updated with a minimum value for ambient light.
Abstract (fin):Diplomityö perehtyy ajovalotekniikan nopean kehityksen mahdollisena sivuilmiönä tapahtuneeseen liikennemerkkien havaittavuuden laskuun.
Kaasunpurkaus- ja LED- valojen kaltaisten teknologioiden korkean valovirran takia on lähivalojen muodostama valokuvio täytynyt rajata terävästi pystysuunnassa, jotta vastaantulevat autoilijat eivät häikäisty.
Samalla varsinaisen terävästi rajatun valokuvion ulkopuolelle säteilevän hajavalon määrä on laskenut.

Liikennemerkit asennetaan tyypillisesti huomattavasti ajoneuvojen ajovalojen valokuvioiden valaiseman alueen ulkopuolelle.
Sen johdosta liikennemerkkejä kohti säteilemä valo on peräisin ajovalojen hajavalosta, tai se on peilautunut ajoradan pinnasta liikennemerkkiä kohti.

Uusien valoteknologioiden, kuten kaasunpurkaus- ja LED -valojen, hyvin tarkkaan rajatun valokuvion oletetaan valaisevan liikennemerkkejä entistä vähemmän.
Vastaavasti korkeatehoiset valaisimet valaisevat ainakin osan ajoradasta erittäin kirkkaaksi.

Diplomityössä liikennemerkkien havaittavuutta tutkittiin sekä henkilöhavainnoilla että mittauksin.
Koetta varten rakennettiin erilaatuisista liikennemerkeistä kymmenen taulua.
Valoteknologioita verrattiin neljällä henkilöautolla, joista kahdessa olivat LED-ajovalot, yhdessä kaasunpurkausvalot ja yhdessä perinteiset halogeenivalaisimet.

Kokeen henkilöhavaintojen ja kirkkausmittausten perusteella liikennemerkit havaitaan parhaiten perinteisillä halogeenivaloilla.
Laadukkailla liikennemerkeillä erot ovat pieniä, mutta heikompitasoisten liikennemerkkien kirkkaus uusilla ajovaloteknologioilla on perinteisiä halogeenivaloja matalampi.
Madaltuneen kirkkauden takia vanhemmat koehenkilöiden havaitsivat uusimmilla ajovaloteknologioilla liikennemerkit perinteisiä halogeenivaloja heikommin.
Nuoret koehenkilöt havaitsivat kaikki liikennemerkit erinomaisesti kaikilla ajovaloilla.

Diplomityön koetulosten perusteella nykyisen ajovalokuvion pohjana olevaan Euroopan talouskomission ehdotukseen tulisi harkita lisättäväksi vähimmäisarvoa hajavalolle.
ED:2014-10-26
INSSI record number: 49930
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