The cache is not accessible from the M40, only from the footbridge/cycleway above it, accessible off the A429.
A simple cache and dash for those passing by. You should be able to find parking close by, near the Motorway Depot.
As I use the M40 every working day I thought I'd add a few caches along the route of this busy motorway to show what you don't see from the carriageway at 70mph. Not always a spectacular view but I hope of some interest anyway.
Please take care when parking not to cause an obstruction and keep watch if you need to cross the road.
Only room for a 35mm micro here.