It was just before seven o'clock on Thursday morning that the police and ambulance were alerted to Ljungarum in the south of Jönköping.
The man, who was seriously injured after the moped accident, was immediately taken to hospital.
According to the police press service, the moped rider is now suspected of drunk driving, illegal driving and negligence in traffic.
The police have seized the vehicle to conduct a technical investigation.
It is unclear how the accident happened.