Thursday, 17 March 2011

Blackfriars - TfL responds. Again, TfL seems to totally miss the point. An annotated response to TfL's latest official view on Blackfriars Bridge scheme

TfL has sent an official response to many people who wrote to complain about the proposed scheme for the junction on the northern side of Blackfriars Bridge. If you'd like to see the scheme and an initial critique of it, click here for more details or read what The Guardian has to say about it or perhaps try the Evening Standard. Surely, we can't all be wrong and TfL knows best?

Below are TfL's comments in black and my annotations in blue. I should stress this are purely my personal comments with some support from other colleagues.

Our Ref: 1008408017/AJ

Date: 17.03.2011
Thank you for your e-mail to Jamila Barrett regarding the planned changes to the cycle lanes at Blackfriars Bridge. As I am certain you will appreciate, we have been receiving a lot of correspondence on this subject recently so please accept our sincerest apologies for the delay in responding to your query. In order to respond to your concerns satisfactorily please permit me to give an overview of the situation before responding to specific points of contention.

The drawing of the proposed changes which was circulated on the internet amongst cyclists’ groups - I think you'll find that the 'cyclists' were worried about this scheme for everyone who's not in a motor vehicle. It's not just about cycling. It's about the rights of all 'traffic' and that includes pedestrians and cyclists to navigate this junction safely and conveniently - was recently issued for stakeholder consultation by Transport for London (TfL). This plan proposed a cycle right turn facility from Victoria Embankment onto Blackfriars Bridge. This element is yet to be approved and subject to change following consultation. In order to put this scheme in context it has been superimposed onto the proposed Network Rail station works in this drawing.

The Network Rail proposal has been approved internally by TfL and City of London, as required under Network Rail’s Traffic and Works Obligation. The drawing for this wider scheme was used for initial engagement with key stakeholders in February 2010. At this initial engagement the City of London consulted the local cycle group Cyclists in the City. - I think that means me. The bright-eyed among you may have noticed that in February 2010, this website didn't exist.

A drawing has now been provided to outline the key features of both schemes and how they differ from the original highway layout prior to any station works.

TfL is acutely aware of the dangers to cyclists which this location has posed in the past. A safety audit has been conducted on both the Network Rail proposal and TfL’s cycle right turn element. Within these audits the safety of the proposals were assessed from the perspective of all road users including cyclists. These audits were carried out in line with TfL’s Road Safety Audit procedure.
In 2004 TfL redesigned the road layout on the bridge to better accommodate cyclists. Perhaps because your previous design was responsible for the deaths of two cyclists It is important to note that whilst proposals are in place to alter the junction due to the upgraded Network Rail station, the road layout on the bridge will not be changed. No-one's asking TfL to change the road layout on the bridge itself. Although a lot of people do think that motor traffic speeds on the bridge should be lowered and see this article for more details about that. Your own Road Safety Unit also thinks the speed limit should be lowered on this bridge.

When considering the proposed changes at the location various modelling programmes were used to assess the effects on all road users. Design development was carried out in the TRANSYT traffic modelling programme to establish the traffic impact of various options. This was supported by LEGION modelling which is a modelling software specifically designed to model the impact on pedestrian movements through and around a proposed junction. This software was used to define the location of the proposed crossings. VISSIM (a more detailed traffic modelling) was carried out in support of the TRANSYT modelling, which included the modelling of cyclists to establish the overall impact of the scheme.

In response to fears that TfL are prioritising drivers’ concerns over those of cyclists, the proposals are giving no more carriageway space to motor traffic, indeed on New Bridge Street the width available for general traffic reduces from 10.6m to between 9.6 and 9.2m wide. Where additional white lining is being provided on New Bridge Street southbound to define an additional lane, this is within the original carriageway width. In the original scheme the traffic behaved in a three lane flow (although this was not officially marked) and by marking in this way lane discipline will be improved, reducing the risk of collisions caused by weaving and side swipes. In other words, you are making the lanes narrower. Your own cycle design guides indicate that where a separate cycle lane is not provided, lane width should be increased to permit vehicles to pass cyclists with a comfortable gap. The organisation of traffic within the junction in this manner will also prevent very significant queuing. What queuing? There has been no significant queuing either northbound in the morning or southbound in the evenings, throughout the current layout.

Unfortunately the proposed scheme requires the removal of the southbound cycle lane outside the station entrance. This is required to accommodate a footway extension. Legion modelling of the expected pedestrian numbers entering and exiting the station has shown that for safety reasons an extension of the proposed footway is required. Furthermore the footway extension is required by DfT to provide sufficient space for station security measures. This is not an explanation – there is no iron rule that says pedestrian space must come from taking away cyclists’ space. No-one wants to remove space for pedestrians here. That space could equally be taken from motor vehicles instead of making cycling more difficult and blaming pedestrians for it when the real issue is TfL's apparent fear of queuing motor vehicles.

Unfortunately it is not possible to extend the carriageway on the western side to provide space to accommodate both the footway extension and the southbound cycle lane outside the station entrance as the tear-drop island is located over areas with limited load bearing due to shallow utilities including a large gas main. Really? So how come it has been possible to drive over this area for the last 18-24 months, without any weight restrictions being imposed, with just a narrow strip island between the two directions? As stated above, it is necessary to mark three lanes of motorised traffic to avoid long queues back through the junction at peak time and to prevent widespread congestion. Again, what widespread congestion? Although three lanes are marked, motorised traffic will not be using any more carriageway space than was originally allocated. Again, you are making the lanes narrower which contravenes your own design standards, the junction has worked perfectly well without the additional lane for nearly two years without any significant queuing, so why revert to that scheme now, just as cycling has taken off here?

TFL is not expecting to see an increase in the amount of traffic using this junction from the original levels in 2008 (prior to any station works). We would also expect to see more constant traffic speeds due to the proposed road markings improving the lane discipline of drivers. In that case, unless you expect a large increase in traffic here, you don’t need the extra lanes because the road functions entirely satisfactorily now with only two lanes.

We have considered requests to reduce the speed of the traffic by imposing a reduced speed limit through the location. 20mph zones are generally more suited to residential areas rather than the principal road network, of which Blackfriars Bridge is a part. While TfL has no objection to the principle of 20mph zones we do not believe that this would be suitable for Blackfriars Bridge. Why? “We do not believe” is not an explanation. And your own Road Safety Unit contradicts you. We've reported here on how the Road Safety Unit proposed in 2008 that the bridge be made 20mph and that there was a clear business case for doing so.

In a number of areas the proposals are giving carriageway space to cyclists. At the southbound New Bridge Street and westbound Queen Victoria Street stop line flares have been removed, reducing the carriageway width from 3 lanes to 2, resulting in right turning cyclists only having to traverse a single lane of traffic where previously they had to traverse two. Advanced Stop Lines (ASL’s) are also being provided for cyclists at all of the approaches to the junction and pedestrian crossings.

Unfortunately the reduction of the cycle lane from 2m to 1.5m northbound through the junction is required to accommodate the widening of the footway which is currently below standard. 1.5m cycle lanes are used throughout central London and are in line with TfL guidance for safe facilities. Here's a 1.5m cycle lane in action on Vauxhall Bridge. It is a terrifying place to cycle. Just because TfL maintains a fiction that this is a London standard does not mean it is. Your own guidelines recommend that you design cycle lanes to be wider than this and that they should be obligatory where possible.  Especially at a point where well over a third of the vehicles using the junction are bicycles. Whilst TfL would prefer to provide a wider cycle lane this is not possible given the spatial constraints of the scheme in this location.

With regards to concerns relating to pedestrian traffic across the junctions, the expected pedestrian movements have been modelled within a software package called LEGION. This was used to determine the location of the proposed crossings to ensure that they are on the most direct desire lines for pedestrians.
Unfortunately due to the expected numbers of pedestrians once the station has been upgraded it was not viable to maintain the temporary crossing in its current location on New Bridge Street. Modelling has shown that the two major desire lines for pedestrians are between the station entry/exit and the eastern and western side of New Bridge Street. It was not considered viable to maintain both crossings on New Bridge Street due to traffic capacity issues. One of those crossings currently doesn’t exist, while the one which crosses New Bridge Street does, is very heavily trafficked, and was a real-life desire line for very many pedestrians long before an official crossing was put there – pedestrians making a quick dash across to the central island, and then another dash to the opposite side in the short gaps between speeding vehicles. So you're removing the major pedestrian desire line because you think the only crossing people want is to and from the station. However, it should be noted that subway entrances 8 and 1 will remain open allowing access between Watergate and the Blackfriars pub.

Finally, we have received many comments relating to the construction of a ‘traffic island’, from the plans, which splits the northbound flow of traffic through the junction. This is not a traffic island. All traffic islands and footway extensions are marked in blue on the latest drawing. So it is confirmed that the cycle lane round the corner by Unilever House will retain the protection of an island. What is being thought of as an island is only proposed to be road marking (hatching) which will be at carriageway level.  Regardless, it is space that could and should be used to protect cyclists turning right into Queen Victoria Street. Instead, you're using the space to create an extra motor vehicle lane.

I hope that the above information has proved interesting to you and goes someway to alleviating your concerns. Please be assured that TfL takes the safety of everyone using the network as a priority. I thank you for your correspondence and apologise once again for the delay in responding to your queries. If there is any other matter which you think I may be able to assist with, please do not hesitate to contact me.

Yours sincerely

Alexander Jackson


  1. Having done some quick research
    LEGION models pedestrian flow only
    TRANSYT appears to not have any bicycle support at all
    VISSIM does support bicycles, their fancy brochure actually has two whole bicycles in a screen shot of their Brandenberg Tor simulation.

    IF two of the three traffic modelling tools don't support bicycles, you can be pretty confident they weren't included in that part of the planning. For the VISSIM simulation, you need to verify what assumptions did they make about the volume of bicycle traffic over the bridge versus car traffic, as if they were using data from a survey taken five years ago a wet winter day, you can be pretty sure its obsolete.

  2. If TfL continue down this path, I think the best approach you can take is to organise some direct action to prevent them endangering cyclists lives merely for the convenience of motorists, who are a minority on this bridge anyway.

  3. Isn't VISSIM the model that only supports bicycles when they represent less than 5% of traffic flow?

    Entertaining though your enraged answers are Danny, the answer from TFL really is a crock of sh*t. They don't seem to get it at all, and their letter is in no way consolatory. It doesn't say 'talk with us about these ideas further', or 'show us how we can help', it says 'f*ck off, we're building it anyway!'. An outrageous response from a public body!

  4. Validation of VISSIM models requires even more care and attention to detail.
    It is a requirement that VISSIM modellers are experienced traffic engineers
    who have studied real traffic behaviour in congested urban networks.

    However, lane utilisation is something the modeller has to carefully define by
    designing the link structure of the model and assigning different proportions of
    traffic demand across the carriageway until the simulated queue lengths
    closely match the actual queues observed during the traffic data collection

    In VISSIM the concept of a “junction” does not exist. Therefore the model
    should have a comprehensive set of priority rules on how vehicles give way to
    each other on paths that are in conflict with each other. The “gap” vehicles
    seek to proceed against opposing traffic should reflect the average minimum
    “time lag” vehicles are looking for as measured during the data collection