Unfortunately, in this litigious age, I imagine that there will be much redesign of golf holes in order to remove the threat of crippling legal costs. Lindrick has already closed one of its old holes and built another to replace it. Hunstanton now has traffic lights on the 18th which are operated by sensors. If you are caught playing a shot while the lights are red you are thrown straight off the course.
I don't think the road crossing St Enodoc does anything to enhance the golf. West Cornwall has public footpaths crossing several holes and these have been sunk below high mounds so that the public cannot be hit as they walk through what must be very like 1st World War trenches. A public footpath passes through the old back nine at Nefyn, and on summer weekends and bank holidays the place is swarming with familes who would be in the utmost danger were it not for the relief holes that have been constructed to avoid this (and to be available whenever there is a landslide - not uncommon). Several public footpaths cross Open Championship courses - Lytham, Hoylake and Royal St George's, for starters. A public road crosses the 17th at Alwoodley. It is a relief that Liphook has now been by-passed, as the old A3 London-Portsmouth main road passed through the golf course (I was there on the unfortunate day when a lady member was killed trying to cross that road). Now the road is very quiet, although it does not affect play. The main London-Portsmouth railway line also runs through the course.
A vast trunk road (the A64 York by-pass) cuts through Fulford and a friend of mine recently resigned his membership because he got so fed up with the steep ramps up to the high-level bridge crossing the road. He now limits his memberships to Ganton and Rye! Ganton has a very significant lane crossing the 17th and 18th. It should not be a factor on the 17th but is very much a threat on the 18th - perhaps the most strategic example of the use of a road with which I am acquainted.
The road crossing Royal Troon behind the 16th green is bordered by deep rough and I have several times lost a ball in there having played too strongly to the green and gone through the back.
The road adjoining the 17th green at Hoylake was a considerable threat - it was not unkown for players to putt off the green and to go out-of-bounds on the road. But the hole is no more.
The road crossing the 9th at Royal Worlington is always in your mind as you pitch to the green.
As a left-hander who slices all too frequently, I am always concerned on the 7th and 8th at Wilmslow, both of which run alongside a minor (but quite busy) road. One of these days I shall hit a windscreen and cause a serious accident.
A road (to the clubhouse and several private houses) crosses the 6th and 9th at Prestbury, although it does not enter the strategy of either hole. Entrance and exit roads cross several holes at Mere and they cause no end of hold ups.
A maze of roads cross the various courses at Wentworth and you can see a great deal of the West Course simply by touring the estate.
Royal Blackheath was closed as long ago as the 1920s because of the advent of the motor car, with a number of public roads crossing the course.
The most recent rebuild at Felixstowe Ferry was done because of potential legal claims with both a road and public paths crossing the course.
Ludlow, too, has suffered the same fate.
Having to cross a terribly busy main road on blind corners is the severe downside to the otherwise admirable Worplesdon.
Moor Park has a number of roads passing through the estate and crossing several holes.
The 1st at St George's Hill crosses a road (which should not be a factor in play) - it is an excellent hole, road or no road.
Several roads and paths cross Painswick, but I played so abominably there that I was rarely on the course and therefore have no clue how they might have affected normal play! Certainly the 17th is seriously complicated by the presence of roads.
On maturer reflection I think only the 18th at Ganton, 9th at Royal Worlington and old 17th at Royal Liverpool are holes on which the presence of the road is a plus factor.
As for railways, how sad it is that steam-powered trains no longer puff their way from St Andrews to Leuchars Junction. The 1st at Prestwick is a great railway hole and I like the 9th and 11th at Maesdu, in North Wales. The close at Sheringham is much enhanced by the presence of a preserved steam railway running alongside. The approach to the 11th at Royal Troon, its green abutting the railway tracks, is always exciting. A railway is also a considerable factor in the close at North Hants (Justin Rose's home course). It's too many years since last I played there, but is it the 16th which plays very tight alongside the railway? The 4th at Woking, of course, is still a good hole because of two bunkers and a railway line.
The little branch line (which is threatened with closure) running through West Cornwall adds to its charms.
We've had a thread on airports and courses recently, but I should just mention Lymm, a little course on the outskirts of Warrington of no particular merit other than the fact that it is build on spoil tipped there when the famous Manchester Ship Canal was built in the 19th century. Few big ships now ply the canal, but I can remember as a child seeing big, ocean-going freighters and tankers in large numbers steaming along the canal. The 6th and 8th holes play along the banks of the canal and the temptation to use a passing banana boat as a moving target must have been great once upon a time.