Yesterday the Mayor published a slew of data on the first year ofthe Silvertown Tunnel. How's it going, did traffic congestion decrease, have noise and pollution got worse, have the new bus routes been a success, is anyone still using the cycle shuttle bus, that kind of thing. There's a 47-page report you can read if you're interested, or you can have some highlights.
Introduction: Over the first year we have seen positive impacts for Londoners, building on the early outcomes observed at three months. The data demonstrates that the scheme’s objectives continue to be met, including managing traffic demand, reducing congestion and improving resilience, while supporting economic and population growth by providing improved cross-river transport links.
Well they would say that wouldn't they? But they might well be right.
Reduced traffic congestion
Congestion and queuing has significantly decreased at both approaches to the Blackwall Tunnel. On the A102 northbound approach to the Blackwall Tunnel from Sun in the Sands, journeys are now more than 58% quicker in the morning peak and 47% quicker in the evening
peak.
I live by the Blackwall Tunnel Approach and can confirm a decrease in jams since the new tunnel opened, at least none that have stretched back as far as the Bow Roundabout. The report states that the total amount of traffic through the Blackwall and Silvertown Tunnels is only marginally lower than pre-April 2025, so not many drivers have been put off by the introduction of tolls.
When the new tunnel opened 77% of traffic carried on using the Blackwall Tunnel and only 23% used the Silvertown Tunnel, but that's now more like 70%/30%. The Rotherhithe Tunnel has seen a 3% increase in traffic, weekdays only, which is lower than predicted. The Woolwich Ferry is being used by about 150 extra vehicles each weekday, although the data's a bit dodgy because the service has been unreliable. Traffic on key road corridors has remained broadly consistent.
A step change in public transport mode share
Bus ridership has grown on the Silvertown and Blackwall Tunnel bus network. More than 30,000 customers now use these buses on an average day. There has been a more than 290% increase in bus journeys across the river. This means that more than 11% of trips through the tunnels are now made by bus.
Obviously bus ridership has grown, there used to be just one under-Thames bus route and now there are three. If you boost the number of buses from six an hour to 21 an hour (a 250% increase), a 290% increase in passenger journeys looks more normal. Also all three bus routes were free to use for the first year and this has obviously distorted the data beyond any fair comparison. Here's a graph comparing before and after.
» Route 108 hasn't changed, other than being free. It's seen a 32% increase in passenger numbers, also delays have dropped by over a quarter due to smoother traffic through the Blackwall Tunnel. I do appreciate a more reliable local bus.
» Route 129 doubled in length when the tunnel opened, weaving onward through the Royal Docks to Beckton. Its passenger numbers have increased by 250% reflecting its new role as a cross-river and Newham-local bus. Being free muddies any long-term conclusions somewhat.
» Route SL4 is new, a Superloop route that does nothing super other than a hyperleap from Blackheath to Tower Hamlets. The report says "it has also proved a success" although you'd expect nothing less, having been free for the first year. I note that of the three routes it's both the least used and the most frequent, thus a lot of empty seats are being shuttled, but TfL "are not proposing any changes to the frequency of routes" at this time.
» Only a third of the passengers on these three routes are actually travelling under the river.
A new cross-river cycling connection
On a typical weekday the new cycle shuttle transports around 100-130 cyclists and their cycles across the river. This is similar to the number of cyclists who use the Woolwich Ferry but significantly higher than cyclist demand at the London Cable Car.
The cycle shuttle bus crosses the river 150 times a day so 100-130 daily users is a pitiful number, on average 0.8 cyclists per bus. Is it lack of underlying demand, the remoteness of the two terminals or an unwillingness to wait for a service to depart? Also numbers plummet in poor weather so when they did a survey in mid-January it was only 50-75 cyclists per day, which is essentially tumbleweed. Graph here. In good news the report says "We are exploring the potential to broaden access to the service to pedestrians", and all I can say is why the hell hasn't this happened already?
Last June they counted cyclists crossing the river in various locations and Tower Bridge came out top with 5000 cyclists in a day. Nowhere east came close. Next was the Greenwich Foot Tunnel with 1324 cyclists, then the wholly unfriendly Rotherhithe Tunnel with 499. The Woolwich Foot Tunnel managed 267, being further out, followed by the Woolwich ferry with just 158 bike crossings. The Silvertown Cycle Shuttle was in sixth place with 127 passengers, despite being the only cycle-specific crossing. And bottom of the heap was the cablecar with, sheesh, just 9 bikes per day. That's despite cycles being free before 10.30am, and what a godawful piece of public transport infrastructure the Dangleway has proved to be.
Improving air quality
Air quality has continued to improve in the area. Compared to the previous monitoring year, nitrogen dioxide concentrations are on average 17% lower and there are no locations where it exceeds the legal limits.
Many pessimists expected air quality to worsen after the tunnel opened, even at sites far from the tunnel mouth. The opposite appears to have happened with NO2 readings decreasing across the board at all locations. The following graph is from a subsidiary report on air quality and, unless you're colour blind, clearly shows an improvement across the suite of 39 monitoring locations.
The only sites still registering over 30µg/m³ are Newham Way in Canning Town and the A2 at Blackheath Hill, both of which previously exceeded 40µg/m³. Reasons given for the drop include a reduction in queueing traffic and a smoothing of the peak period. It's not clear how much of the fall is due to the tunnel and how much is a wider London effect following the spread of ULEZ, but as someone who lives close enough to the A12 for this to make a difference I'm delighted to finally be breathing less in.
