Rhiryd Wyn Hughes faces three charges of indecent exposure, and of misconduct in a public office.
Northamptonshire Police say the collision involved a cyclist and the driver of a black Audi A4.
Police refer themselves to a watchdog because officers had contact with the man before the crash.
The police station will occupy the building that used to be Jurassic Grill.
The eastbound carriageway has reopened but the westbound remains close, says National Highways.
Police say the behaviour is having "a significant impact on residents and the wider community".
National Highways says emergency services were called to the scene.
Eight people have been arrested after Khadeem Parris died on 7 July, police say.
Special constable Sophie Hyde says her "fight-or-flight" instinct just kicked in.
