Around 35,000 people are expected to attend the celebrations which take place at sunrise on Saturday.
Stonehenge will be open for the celebrations between 19:00 on Friday 20 June to 08:00am on Saturday 21 June.
People attending the event are being encouraged to use a frequent special bus service running from Salisbury throughout the Friday night and into the next day to avoid delays reaching Stonehenge.
Road users travelling by Stonehenge on the A303 are advised to plan their journeys in advance and allow longer to reach their destinations.
See Salisbury Reds Summer Solstice bus service
Members of the public should contact the Highways Agency Information Line on 0300 123 5000
Journalists should contact the Highways Agency press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.