Traffic jams occurring on highways cause increased travel time as well as increased fuel consumption and crashes. Traffic jams without a clear cause, such as an on-ramp or an accident, are called phantom traffic jams and are said to make up 50% of all traffic jams. They are the result of an unstable traffic flow caused by human driving behaviour. Recent studies have shown how automating the longitudinal vehicle motion of only 5% of all cars in the flow can dissipate phantom traffic jams. However, automation introduces new problems, mainly regarding safety when human drivers need to take over the control. This research tries to answer whether phantom traffic jams can be dissolved or prevented using haptic shared control. This means of control keeps the human in the loop and would therefore eliminate the takeover problems while still benefiting from the advantages of automation. 24 participants took part in a driving experiment in a fixed base simulator. In these experiments, we tested haptic shared control against manual control and full automation for longitudinal motion. Results show that traffic jam dissipation performance for haptic shared control lies between manual control and automation. The number of unsafe situations is reduced compared to the automated condition. We conclude that haptic shared control is able to reduce the increased fuel consumption and crashes caused by phantom traffic jams.