A survey by the Swedish Quality Index (SKI) gave SJ a customer satisfaction score of 55.9, which according to the index indicates that the company may struggle to keep its customers.
Long-distance coaches got the best score, with 74.9 for Nettbus4You and 72.1 for Nettbus Express.
Air travel also got comparatively high scores, with a 70.5 point score for BRA, which mainly operates domestic flights, and 69.7 for Scandinavian Airlines (SAS), part-owned by Sweden, Norway and Denmark.
The survey was carried out in April, so it is unlikely that the SAS pilots' recent strike – which grounded thousands of flights for seven days and caused widespread customer outrage – affected the score.
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In general, the long-distance coach industry saw the highest customer satisfaction rating, with a score of 70.2 in the SKI survey, compared to 66.8 for airlines overall and 61.2 for rail travel.
Environmental sustainability was an important factor for respondents, but also key was how the companies handled delays and disruption and kept customers informed, according to SKI.
A total of 2,222 people responded to the survey.