Range comfort zone of electric vehicle users – concept and assessment

Enhancing usable range and the range-related user experience in battery electric vehicle (BEV) use is an essential task in advancing electric mobility systems. The authors suggest the concept of comfortable range (i.e. the users´ range comfort zone or range safety buffer) as a benchmark variable for evaluating range-optimisation strategies. A methodology for assessing comfortable range was developed over the course of three BEV field trials. Here the final methodology is described and evaluated which consists of the comfortable range scenario task (CRST) which indirectly assesses comfortable range as well as several single-item indicators that directly ask respondents for comfortable trip distances or range safety buffers. Results show that the developed comfortable range indicators have good psychometric characteristics (internal consistency, factorial structure and test-retest reliability), are able to depict the known effect of behavioural adaptation to limited range, and correlate with actual range utilisation behaviour. The CRST performs more robust than the single-item indicators within this evaluation.