Wednesday, 24 June 2009

Cycling City - There's none so blind.....

One of the basic considerations in highway design is to have adequate sight lines at bends and junctions to avoid blind corners. Visibility should of course be appropriate for the design speed of the highway. It's so elementary it hardly needs more explanation....unless you happen to work for our Cycling City project it seems.

Here we have the only significant bit of Cycling City infrastructure to have been completed so far, the upgrading of the old path through the St Werburgh's allotments and alongside the mainline railway to Muller Road, now known as the Farm Pub Path. The engineering of the path is generally good but, as ever, the devil is in the detail.

Here's another example at the old Ashley Down station site, the high point of the path before it drops back down to Muller Road. The path from St Werburgh's comes up from the right in the foreground while the path on to Muller Road heads off to the left. The straight-though path passing through the subway also links to Muller Road at the junction with Shaldon Road but is not intended to be part of the main route.

Cyclists using the main through route are supposed to give way to crossing movements on the minor route, which of course they will be reluctant to do. That's why the century-old convention is for minor routes to give way to major ones, but such tried-and-tested conventions, like the need for sight lines, are routinely ignored by our Cycling City route designers who apparently know better.

Here's the particular problem at this junction (above), looking at it from the point of view of someone coming up from Muller Road on the main through route. You arrive at the intersection but cannot readily see if anyone is coming down the hill due to the fencing. Below is the view for someone heading down the steep incline to the subway - again they cannot see if anyone is emerging from the main route, particularly as vegetation obscures the limited visibility through the fencing. All that was required was for the fencing to be set back a metre or so at the corner.

Now you may be thinking this is another example of Chris Hutt making a mountain out of a molehill and exaggerating the significance of minor details. So here are some unsolicited and independent comments by another user which were recently posted on the Bristol Cycling Campaign web site -
"The new speed opportunities of this widened and well-surfaced path have
almost knocked me flying twice in as many days. Watch out coming UP from near the pub where you curve round to the 'T junction'. First time, unawares, I was enjoying the view, when someone hurtled past from the left as I was about to turn right. Today I was watching super-carefully, climbing towards the junction on LHS, when a youngster on BMX, apparently unable to steer leftwards or brake, sped down at me and just squeaked through on my left as I ground to a shaking halt! Hate to be a killjoy, but fear we may need cycling speed bumps or signage?"
You see designing cycle facilities is not something that can be left to the officer who failed to make the grade as a highway engineer. It requires much the same understanding of the dynamics of handling traffic as do normal roads. Speeds of 20 mph are not unusual and closing speeds (two cyclists approaching from opposite directions) could easily exceed 30 mph, enough to result in serious or fatal injuries. Design has to be based on realistic expectations of users' behaviour, as it is for general roads.

I have offered the advice many times in this blog that it is crucial that competent professionals are engaged to oversee Cycling City, but it does not appear to have been taken. We have technically demanding cycle routes being designed by people who seem to think they're designing footpaths. It's only a matter of time before people are seriously injured as a consequence of such design defects and they will be entirely justified in suing the council for all they're worth.


Jon Rogers said...

Thanks as ever Chris

Your observations have been passed to officers.


Noel said...

Whats with that post right in the middle of the path on the last pic? Who ever thought that was a good idea?

Chris Hutt said...

Noel, the post is the lamp standard that I think was always there. Nevertheless the opportunity could have been taken to move it to the side, so removing an obstacle and improving visibility at the junction.

However the cycling officers seem to think it a good idea to stick black-painted posts in the middle of cycle paths and do it all over the place, including on this path.

I can see why bollards may be sometimes appropriate to stop access by motor vehicles but why on earth do they insist on painting them all black so making them hard to see? It isn't allowed on roads used by motor vehicles for obvious safety reasons but for some reason cyclists are expected to look out for them.

SteveL said...

* Post is there to stop stolen cars getting all the way down and jamming the bridge. It used to be further downhill, but got moved up a year or two back.

* you can go straight on at the St W end, and then either do the very steep footpath up (tricky) to connect to the sefton park prth, or nip behind the pub to get up to Ashley Down road through the allotments.

* as you come down the path towards the farm pub and that left turn, at slow speeds you get some visibility through the railings. Once you let go of the brakes though, all visibility is shot, and the junction comes up very fast.

* check out the bike skid marks on the path already. People are having fun out there.

Chris Hutt said...

Thanks for that feedback Steve.

On visibility through the railings, that is rapidly going to disappear as vegetation grows over them. Perhaps a convex mirror would give people a means of seeing around the blind corner?

Had I been designing this route I think I would have tried to rationalise the routes at the St Werbs end. There's really little point in having the path split into two at the end.

If one path were sacrificed to the allotments in exchange for sufficient land to sort out the other then one might have ended up with one path with decent sightlines. It was obvious from the outset that the existing arrangement was going to be problematical.

Whatever problems are already manifestng themselves, imagine how much worse it will be in October when the clocks go back and much of the action is in the dark with nothing better than those daft little studs to illuminate the way.

Docsavage said...

come down station road (steep) and try and join the path turning right at anything other than a crawl and you leave the path. There's a lovely adverse camber that helps tip you onto the earth too.

At the other end I've already impacted with a young guy on a BMX with apparantly no brakes (he kindly shouted 'NO BRAKES!' at me just before hitting me)
So no, chris this isn't nit picking. and As I mentioned the other day, the council now need to sort out the access up and down Mina Road. as every evening the young yuppies (can I call them that?) love to park every which way on the way to their mountain climbing. The cycle lanes are full every night with parked cars.
The cycle access points into the tunnel are another gem - Mr Whitehead admitted to me in an email some time ago that they were in fact badly designed and frankly not fit for purpose, but there they are, either forcing you at 90 degrees into parked cars or forcing you into the middle of the tunnel to meet oncoming vehicles - Huzzah!

David Wilcox said...

It seems all my concerns about this route have been realised. When I raised these issues when we did the site visit, I was told that the Cycling Team where taking 'a suck it and see' approach to this cycletrack. This might work for buying a CD from Fopp but not for design and implementation of a heavily used cycle and foot way.
I wonder how much money it will take to fix this already over budget and late project?

McD said...

I commented on this layout when I first saw it at partial construction stage and asked about putting iin some zig-zags or similar to make the uphill easier - this after having led a ride of "gentle" cyclists up this very steep incline and several getting off to walk (nothing wrong with walking a bike I know). Perhaps a re-design of this section could reduce the steepness with some zigs making it easier to cycle up, reducing speeds on the descent and making it easier and safer to traverse on the main path.