Thursday 11 December 2008

A roundabout failure

Apparently the police were out on Zetland road on Wednesday morning, enforcing traffic rules on cyclists. This means sadly, that nobody was around at the top of the hill, St Michaels Hill mini-roundabout, to enforce traffic rules there. Such as the "do not block a junction" rule.

Roundabouts are probably the ideal junction as far as the Association of British Drivers are concerned. No lights, no pedestrian time to stop cars getting through, cars get right of way over any schoolkids trying to get from one island to another. Sadly, queue theory, one of those pesky little things the ABD don't agree with (along with pollution statistics, finite fuel supplies and global warming), kicks in here. It is impossible for more vehicles to enter a roundabout than leaves it. If the majority of vehicles are heading in the same direction -here down St Michael's Hill and then to the city centre-, then the maximum load of the roundabout is the same vehicles/hour as that single road can sustain. At this point, law abiding cars will stop and wait patiently for the junction to clear before pulling out. Here we some some waiting patiently and only blocking traffic leaving Cotham Road.

Soon they are joined by a car full of school kids, WP05VXC. There is still enough room for cars turning right off St Michael's hill to get through to Cotham Road, though visibility is hampered.

As the traffic crawls forward, a Range Rover pulls out to take up the space. No cars can turn right from Cotham Road to Hampton Road. No bikes can get over to go down Cotham Hill -it's bikes only in that direction. Hampton Road to Cotham Road is the only routing that is still live.

The range rover L12BXF is soon joined by a red Toyota from Cotham Hill. The RR hasn't moved that far forward, so now the line of cars continues across the junction.

A pickup from Cotham Hill now seizes the opportunity. Unfortunately, the Toyota (kids inside again) prevents the pickup behind it from even completing the turn; it has to sit with its indicators on. Blocking the exit for any vehicles heading up Hampton road, such as the two vans behind it.

There we have it. A complete roundabout failure in the space of 30 seconds. The throughput of the roundabout becomes that of the slowest moving road off it: 0 vehicles/hour, so delivering the same throughput to anyone trying to head in any direction off the roundabout.

What could be done to prevent this? Perhaps we could have someone issue spot fines for vehicles blocking a junction? Perhaps a local newspaper could start a campaign against people who seem to be going out of their way to inconvenience cars? Here at Bristol Traffic, we think such persecution is uncalled for, and would be another sign of an anti-car city.


Chris Hutt said...

Yes, much better for the police to persecute some unpopular and harassed minority group like cyclists than deal with the real traffic problems.

Anonymous said...

I saw this comment from Chief Inspector Andy Bennett, who was leading the operation, who said: “This is in response to complaints from the public to the police, to Bristol City Council and in the Post." on the thisisbristol article about the response to their "crackdown".

Why don't you publish the relevant email addresses for:
Avon & Somerset Constabulary
Bristol City Council
The Evening Post

Then we can email complaints to them about every piece of road traffic law breaking we see when we're out and about.

Chris Hutt said...

The police won't give out their email address. They don't want to communicate with us, just at us.

SteveL said...

Bristol Parking Services do not read their email or answer their phone after 5pm. Avon Polis do have email addresses, we need to collect them. They also have a premium phone number to make calling them from your mobile more expensive.

We were thinking of organising a report bad parking day in which we report in every parent on the pavement outside a school; every car on a corner, every minicab on a bike lane, for a single day. Then follow up the next day with queries to see what actions were taken.

green tomato said...

Those email addresses:
evening post - try

police officers are so try andy.bennett or andrew, or even gordon if that's his real name.

The boss of parking services is and he does answer emails.
For those who don't know already, parking services (phones manned 9-5) only deal with vehicles illegally parked where parking regs, ie yellow lines, exist .
If car obstructing pavement or road and no yellow lines, its police, usually PCSO's. Contact them through your beat officer, find them through the police website, or ask your councillor. Or just have a chat to them when you see them around.
So the roundabout is a police issue - but if no yellow box, and roundabouts don't usually have them, then they would have to use the 'obstruction' law which might be harder I imagine.

Bad Parking it!

Anonymous said...

I'm sick of this, I've been trying to cycle round Bristol for 20 yaers, been hospitalised twice and now stopped and fined meters from my house for mounting the pavement as I reached home. The only way to be safe traveling round Bristol is in a car, nobody else will be safe because I'm a nervous and not very good driver, but at least I'll be OK. Cycling city - what a sick joke

SteveL said...

@Anonymous -did you get a ticket? Get in touch at bristol.traffic at When the govt introduce spot pavement fines, they explicity stated it was not for people who had good reason to be scared of the road, so you should be able to fight it. We can push back on this.