How many bollards does a bridge need?

The Bourg Walk cycle, and pedestrian, bridge
that is the centrepiece of the town's pro-cycling program.
Five bollards at one end.
Just how many bollards is TOO many?

Reading a post on another blog got me thinking about bollards on cyclepaths.

Five bollards protecting the "Bourg Walk" bridge in Aylesbury from errant motorists (and I suspect teenaged scooterists as well).
By the way, if you look up the Bourg Walk bridge on Google Maps, it isn't shown on the satellite view yet, and neither are the changes to the local roads that came with it, although someone has helpfully marked it on the map where it is (the namer is shown in a carpark, which the bridge crosses the edge of).
I guess it will be at some point in the future.

Just how many bollards are too many?



If the purpose is to restrict the maximum size of vehicle crossing the bridge, then the outer pair of ballards are placed too close to the edge. The maximum vehicle width in this case would be for a vehicle passing diagonally between the central bars, not through the gap at the edge

If the purpose is to stop folks rushing down the slope and onto the road behind (there is an urban dual carriageway a.k.a. "divided highway", with, in this case, two lanes of traffic in each direction a few yards (c. metres/meters) behind me), then would not the more common "baffle" type of restriction work at least as well. these usually have a barrier covering somewhere between 50% and 75% of the width of the pathway, and often have a top bar with a space underneath so that push-chairs and such can often be passed under them, although an adult would have to crouch quite a bit to pass through, and would go around instead.

The bollards are pretty heavy duty steel posts, too. So one has to be careful after dark, because if you hit them, you will bend, not the posts.

Crossing the bridge, which is the "centrepiece" of the town's cycling program would be problematic with a trailer, too. There is a chap that I see cycling around town with a nice trailer that has a decent-sized locking metal box mounted on it - it looks a bit like one of those fairly large equipment "flight cases" used for moving various delicate stuff. I have seen him using it for leaflet delivery in a few parts of the town. Next time I see him, perhaps I will ask him how he gets on with the bollards.
And perhaps it is just as well that "cargo trikes" and "kiddie trikes" (Practial Cycles, for example, has a range of such bikes/trikes for sale) are not very common here, either. I know they exist in the UK, but I have never seen one locally.

So, what do you think?
How many bollards is "too many"?
What is the bollard situation like where you are?