A 17-year-old boy has been charged with arson and endangering road users after bomb disposal teams were called to "potentially hazardous material" thrown onto the M3.
Hampshire Police said the teenager had been charged with two counts of arson with intent to endanger life and two counts of causing danger to road users following incidents on the motorway on 16 and 23 September.
Thousands of drivers were caught in two-mile queues after police shut the M3 near Winchester while explosive experts examined potentially dangerous material thrown from a bridge last week.
The major road was closed for 11 hours on 23 September as fire crews, police, and the Ministry of Defence's Explosive Ordnance Disposal team investigated.
The motorway, which runs between London and Southampton, was shut in both directions between junction nine and 11 from 4am to 3.30pm, causing chaos for motorists.
Police said early assessments had found the material was "flammable, not explosive" but tests were still ongoing. Nobody was hurt.
Detectives said there was "no wider risk to public safety" and the incident was not related to terrorism.
A week earlier, motorists told police they had seen a flaming object being dropped onto the carriageway from the same bridge. Officers attended but found only broken glass and no fire.
The teenager, from Winchester, was remanded in custody to appear at Basingstoke Magistrates’ Court on Monday.
