Guidelines for adapting the vehicle interior for comfortable smart phone use.

Passengers often use a smartphone while traveling in the train, airplane, bus, and perhaps in the future in the automated driving car. Ideally, future designs should support this smartphone use to prevent discomfort. The smart phone is often used with two elbows on the armrests. However, the armrest height could be too low and cause neck flexion. This study focuses on a guideline for the appropriate height level of the armrest while using the smartphone. Participants performed four main smart phone activities: listening to music, texting, watching, and reading on the phone in a train seat. The anthropometric data, and the neck, trunk, and elbow ankle were recorded. Based on these data the height level of the armrest was calculated. The results show that the height level of the armrest should be adjustable between 184-295 mm. above the seat pan. If there is no possibility to make it adjustable 243 mm is advised. Future steps could be the design and mechanism of the armrest, or another tool that can help to hold the smartphone.