There seems to be lots of guys here posting courses that have road crossings, and the final count would probably be more than 25 of the top 100 courses, that have some sort of private or public carriageway in the midst of the routing, by the time it's all done.
Simply because some courses do have road crossings, isn't a compelling case to say that a course should cross a road(s). Imagine how good the courses and experiences upon those courses would be if they didn't have to have the crossing interfere...
In TD's example, he's not talking about the small road in and out of a course, like we see at Pebble, where one simply traverses a paved segment, to get from #15 tee box to landing area. He's talking a big, noisy, wide, high volume road, which seperates one green, and the next tee, by a reasonable way.
My experience has been that the roads significantly detract from the total experience, and enough such that they should be avoided wherever possible. The down-grading of Royal Melbourne East, by a large number of experts, is due to the road crossings, and it occurs despite the contribution of 6 high quality holes to the Royal Melb Composite layout, and many other quality holes on the other sides of the crossings.
Tom - I'd avoid it if I could, unless there's a very large problem arising in being contained on one side of the road, or if there is some sort of nirvana on the other side.
I know some will think - "the client is a land developer, so what does he care? I'll cross the road". I know others here will also think "this course bears my name and it will be the best it can be". I'm tipping you're the latter Tom....
MM