Wednesday 28 September 2016

Tower Bridge

Sorry, it's a London-centric post this week, but there's application for many situations. The iconic Tower Bridge is closing for essential maintenance for three months and it presents an opportunity.

The venerable structure is being closed between 1st October and 30th December for major planned maintenance and so drivers and cyclists will be diverted elsewhere and other than a few weekends, it will be available for pedestrian use only (a ferry is planned for full closure days).

Tower Bridge and its approach roads are the A100 and form part of a rough circle of A roads around The City which also run in some of the other adjacent boroughs. Some of the A roads around the area and indeed within the area are A roads in classification, rather than design in that they were never designed to take high levels of motor traffic, its a network which evolved.

Southern approach to Tower Bridge.
Tower Bridge is often held up as being strategically important as the next crossing of the Thames (for motor traffic) is the Rotherhithe Tunnel some 2km east and then we have the Blackwall Tunnel a further 3km east of that (as the crow flies). Tower bridge carries all classes of traffic up to 18 tonnes, including 3 bus routes, and so it is pretty important locally with delivery lorries, taxis and private vehicles. There is also a 20mph speed limit which along with the weight limit, helps manage the loading on the historic structure; both are camera-enforced.

From a walking point of view, the footways are reasonably wide, but they can often get busy with tourists which is what one would suspect. From a cycling point of view, there is no infrastructure and what you tend to find is that drivers often try and overtake you on the approach roads before the main span of the bridge which is much narrower - it's awful as are the approach roads themselves! On the north side, the east-west CS superhighway passes within 500 metres.

The Google car captures the conditions for cycling!

Traffic-wise, we have a Department for Transport count point on the A100, just south of the bridge;


Since the year 2000, there has been an almost 40% reduction in motor traffic crossing Tower Bridge. There has been some fluctuations and in 2015, there is a hint that traffic might be growing again. LGVs and HGVs have dropped by 22% and 26% over the same period, with motorcycle use dropping about 40%. Cycle traffic has grown 140% in the same period and as a percentage of all traffic, cycling has gone from less than 3% to 20% which is astonishing given how awful it is to ride there. Bus/ coach traffic has stayed fairly consistent.

The closure will affect motor traffic and cycle traffic with separate diversions for people travelling northbound and southbound. Northbound will be via London Bridge some 900m to the west and southbound traffic will be via Southwark Bridge which is another 450m to the west. There are also other restrictions designed to make the diversions work.

It's an interesting time of the year for the closure as it will be through the Autumn and into the run up to Christmas which is a time when traffic levels tend to be at the highest; the Summer holidays would have been more usual, although we only have 6-weeks then. Also, bridge works taken place at this time might have more weather interference, but the decisions will have been taken by The City which manages the bridge and in turn they may well have had to coordinate with other major works in the area.

So, what is the opportunity? It would be a perfect time to get some traffic monitoring out on the road network in the surrounding area to see what the impact on traffic flows and congestion is. This could provide data to enable a discussion to take place on how traffic is managed in the future. Unlike a good wine, bridges don't improve with age and they need increasing amounts of investment to maintain any given level of service. Tower Bridge is Grade I listed and 122 years old and is having its timber decking refurbished for the first time since 1970. 

The discussion we should be having is whether or not we should continue to allow so much motor traffic to use Tower Bridge. It would be simple to use a traffic management order to restrict the bridge to buses, taxis and cycles (with exemption for emergency vehicles of course). From a cycling point of view, it would still mean mixing with traffic and there would be no gains for people walking.

To go further, we could run a contraflow over the bridge controlled by traffic signals - there is stacking space either side. This would free up space within which cycle tracks could be provided;




OK, the dimensions are a bit rough (I've taken from Google), but it shows how the space could be rebalanced to enable cycling. Away from the bridge, there is plenty of space for cycle tracks and wider footways. This type of thinking could take place on any bridge which is showing its age and as ever, we are dealing with the politics of space.

18 comments:

  1. The level of investment is up to Bridge House Estates isn't it? They're quite well endowed so this is oddly one piece of infrastructure where lack of funding (for bridge works) probably isn't an issue.

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    1. Blimey, yes - they do have a few quid stashed away! https://en.wikipedia.org/wiki/Bridge_House_Estates

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    2. Except that these bridge trusts are not renowned for actually *spending* money... (google the Clifton Suspension Bridge Trust some time).

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  2. Great! Any idea who would be responsible for doing the traffic monitoring? Who needs contacting to get this going?

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    1. I guess it would be a joint effort by Southwark, The City and TfL

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  3. The bus lane need not be that wide. 3.1 metre wide lanes works
    well, although 2.75 will tolerate a bus, 2.5 for turning lanes at 70 km/h or less. The remainder of the space can have a .5 metre wide kerb between bikes and buses and a 4 metre wide bidirectional cycle track with the footways only modified so as to have a forgiving curb, 30 degrees on the side next to the cycle track and 45 on the side facing the bus lane and the same principle on the kerb between the bus lane and cycle lane.

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    1. Oh, it was just a rough layout to show the concept - the measurements are estimated from Google, so there may be more or less space in real life!

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    2. +1 for narrower bus lane(s). If stacking is deemed problematic (pollution, timetables, emergency vehicles etc) then perhaps one shared bus/cycle lane in each direction, with strictly enforced no overtaking if required, for the 3-400m of bridge, then use the space on both approaches for protected cycleways instead of stacking areas?

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  4. I live right next to Tower Bridge and am wholeheartedly in support of making it cycle+public transport only. It is one of the great attractions of London, perhaps even the world, and the continuous heavy traffic is frankly embarrassing.

    Unfortunately the timing of the closure isn't great. The redevelopment of London Bridge station and one-way operation of Tooley Street is having a big effect on traffic in the area, and it will only get worse when TB is closed. Even if the incremental impact is small, the general public will associate the work on TB with even more congestion and politically it's going to be hard to push through. Brave leadership required, and can Southwark Council / City of London do it?

    PS - have you seen the diversion routes for cyclists? Heading east, the alternative route via Southwark Bridge adds an extra 2 miles to your journey.



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    1. Yes, the diversion is long and route pretty awful; I don't know if working on the bridge deck in two halves to maintain cycle access was thought about or indeed practical.

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    2. Maybe the thousands of riders could wheel their bikes across. Hilarity to ensue.

      Jitensha Oni

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    3. Well I assume people are free to do this!

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  5. With Tooley Street closed what an opportunity to really reduce traffic churn in this 'bulge' between Bermondsey and Blackfriars (or even Lambeth) Currently most traffic is being kept on the Old Kent Road to Elephant/Borough and moving to the South.

    Your photos don't really do justice to Tower Bridge at peak times/most of the working day when it is a solid 2-lanes of slow moving and stalled motor traffic, which cyclists than filter past - no great surprise then that cycle traffic has increased, especially as many city companies have relocated to OneLondon, but their employees still commute from Essex and Hertfordshire in to Liverpool Street/Fenchurch Street and there is a notable absence of a tube line connection across the river between London Bridge and Rotherhithe neither of which works well for 2 of the 3 City rail terminii

    Maybe a quick & simple concrete tube dropped in a trench in the Thames mud from Potters Fields/City Hall to connect with Tower Hill's station access passages ... possibly pop-up through Traitors Gate at The Tower

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    1. It's a good point about those London terminals - no easy way to head south - perhaps a parallel walking and cycling bascule bridge!

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  6. Why do private motor vehicles and taxis *have* to cross this bridge at all?

    Do buses need to run in both directions simultaneously or are the passengers loads tidal, thus presenting an opportunity to introduce a reversible bus lane that changes direction twice a day?

    If people walking and cycling on this bridge are the major mode shares, even potentially, then they should be catered for first.

    Think BIG! A closure such as this is the ideal time to make such permanent changes when there are reasonable alternative routes nearby. Utilitarian bridges users will adjust their travel patterns during construction and these will become the new normal for them and they will struggle to even remember their old ways.

    This iconic structure and major tourist attraction us currently befouled by motorised traffic the same way the Rijksmuseum tunnel used to be.

    And what a win and a statement for cycling/active travel/"the people" etc it would be.

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    1. Think big indeed! My only concern was that being the last crossing for a while, there might be issues with gaps in bus routes which would disadvantage users; hence the signal control would allow access, but free up space for cycling.

      But yes, it's an icon which has been appropriated by motor traffic!

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    2. Tower Bridge is the only one for miles not in the congestion charging zone. Unless the zone expands to benefit more of the city, I foresee a rather large pushback from people who otherwise wouldn't have to enter it.

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    3. Oh it's not an easy idea to sell by any means!

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