A 42-year-old man has been arrested on suspicion of attempted murder after a Mercedes van carrying gas cylinders caught fire.
Police officers and three fire crews were called to the fire in a layby on the A41 between Aylesbury and Aston Clinton just after 11.30pm on Monday.
They set up a 200 metre cordon while they tackled the blaze. The driver of the Mercedes Sprinter, a 47-year-old man, managed to escape but was taken to hospital with minor injuries.
A 42-year-old man from Tring has been arrested and is currently in police custody. The fire is being treated as arson.
Investigating officer, Det Sgt Simon Johnson, said: “I would like to reassure the community that we believe this was a targeted attack on the 47-year-old victim.
“If anyone saw or heard anything suspicious in the vicinity of the A41 between Aylesbury and Aston Clinton last night please contact police immediately.
“I would like to thank motorists for their patience while the A41 was closed while we carried out our enquiries at the scene.”
The bypass was shut in both directions between the A41/Icknield Way (Crows Nest Roundabout) and the A41/London Road (Woodlands Roundabout).
As police carried out their investigations yesterday morning, and the acetylene cylinders were cooling, the road remained closed but it reopened at midday.
Anyone with information is asked to call 101. Alternatively, you can contact Crimestoppers anonymously on 0800 555 111.
No personal details are taken, information is not traced or recorded and you will not go to court.