Drivers' impressions under high-pressure sodium and LED street lighting

Abstract

In order to compare drivers' subjective impressions when exposed to high-pressure sodium versus LED street lighting, an experiment was conducted on a Belgrade street. All general requirements for an adequate comparison of subjective impressions, equal luminances being the most important, were fulfilled. A survey was conducted using a questionnaire, which the respondents filled out immediately after driving through both zones of the illuminated street. The respondents, who were young drivers (students), aged 20-25 years, were asked to select the more appropriate of the two installations regarding seven lighting parameters as well as giving their overall impression. The two regimes for which the survey was done gave opposite results. In the normal regime, where both installations had the same photopic luminance, the LED installation was evaluated as a better solution by a majority of the respondents for most of the analysed parameters. In the mesopic regime, where both installations had the same mesopic luminance, most of the respondents judged that the high-pressure sodium installation was the better choice.