https://www.google.co.uk/maps/@52.6720363,5.0523774,3a,75y,264.92h,83.69t/data=!3m6!1e1!3m4!1sUuiu3NOQrddDgwvaIE5AyQ!2e0!7i16384!8i8192?coh=205409&entry=ttu&g_ep=EgoyMDI0MTAwMi4xIKXMDSoASAFQAw%3D%3D

Shows the N307 road in the Netherlands, where it is crossed by the Hoorn-Medemblik heritage line. This runs service once a day each way (twice in busier months).

The heritage line crosses another dual carriagway; it also has a large number of other level crossings, including one shared with NS trains.

A heritage railway has recently done that. Getting approval from the ORR^» (Office of Rail and Road formerly Office of Rail Regulation - about) and Highways England to build a level crossing across an A road.

The Rother Valley Railway has its Transport & Works Act Order to build its line from Robertsbridge station to join up with the Kent & East Sussex Railway to the west of Bodiam station. The route includes three new level crossings, including one across the A21 Robertsbridge bypass.

https://www.rvr.org.uk/

https://www.gov.uk/government/publications/bodiam-to-robertsbridge-junction-order-transport-and-works-act-order

The Welsh Highland Railway leaves the Harbour station at Porthmadog, shared with the Ffestiniog, then shares the high street (A497) over the Pont Britannia before leaving the tarmac behind on the 25 mile journey to Caernarfon. A really worth while trip, I suspect permission was granted because of the recently built bypass of the town.

My opening post was inspired by memories of this crossing of the A5 by the Oswestry-Gobowen route:
https://www.google.co.uk/maps/@52.8799055,-3.0396629,3a,75y,163.66h,66.38t/data=!3m7!1e1!3m5!1sorfHRxIvMQr_pJKui5iU6g!2e0!5s20240701T000000!7i16384!8i8192?coh=205409&entry=ttu&g_ep=EgoyMDI0MTAwNS4yIKXMDSoASAFQAw%3D%3D

I'm not sure if it would qualify as heritage these days as the rail route became the subject of an RYR^▸ (Restoring Your Railway) application for a light rail service.

I was involved with that railway in the 1980s and it faced a very real threat from the building of the Wallingford bypass.  Already truncated at the town end, it was facing the prospect of being cut in two with neither half likely to be viable. 

After much negotiation agreement was reached and the crossing installed.  I am aware of at least two incidents at the location since - neither resulting in serious injury - but in the main it has worked well.