Reality check: will 'Crossrail for bikes' bring gridlock to central London?

What is planned?

The cycle superhighway will be made up of two routes, one going three miles north-south from King’s Cross to Elephant and Castle and the other travelling 18 miles east-west from Barking to Acton – making the biggest continuous, substantially segregated urban cycleway in Europe.

What are the next steps?

A public consultation has been extended until 9 November and, if all goes to plan, work will begin next year and the routes will open in March 2016.

What effects have similar projects had?

The London Cycling Campaign’s chief executive, Ashok Sinha, says fears of London grinding to a halt are unfounded:

There will be a 40% increase in people working in central London Boroughs over the coming decades. Promoting cycling will not be the cause of congestion, it will be essential to keeping London moving.

In New York, the addition of more than 30 miles of protected bike lanes since 2007 has actually sped up motor traffic on some stretches, according to this data analysis.

More recently, in Seattle, converting a one-way cycle lane to a two-way, protected cycle lane tripled bike traffic on the first three days after its opening, the Seattle Department of Transportation said.

The London mayor’s office says:

Segregated cycle lanes have been proven to promote economic growth in other world cities, with retailers along their routes reporting sharp growth in customers and spending as the streets become more pleasant.

What are the main areas of concern?

Many are worried about the effects delays to motor traffic will have on businesses on the capital – whether that means longer commutes or delays to deliveries.

The AA president, Edmund King, says the motorists’ association is “generally supportive” of the plans and the general principle of dedicated cycle routes was good for all road users. But adds:

However, some sections of the route have raised a few eyebrows. In particular the Westway – as a cyclist I wouldn’t fancy cycling along an elevated section of what is basically motorway – so we will be going back and perhaps suggesting other routes. As a driver there is nothing worse than a cycle path that runs for 50m then fades out and it’s the same for cyclists – it creates a false sense of security.

Tom Platt, the London manager of pedestrian organisation Living Streets, says:

Encouraging more people out of their cars, getting them walking, using public transport and cycling will make London a more liveable city but pedestrian safety and amenity must not be compromised.

Living Streets is concerned at plans to increase pedestrian waiting times at several crossings, including outside Blackfriars underground station where the wait will be increased to two minutes. That is a very long time to wait and could encourage people to take more risks.

Will the plans really cause a huge increase in congestion?

Transport for London has released traffic modelling data for the cycle superhighway schemes showing that the east-west route will cause an average delay of 1 minute 26 seconds to cars travelling along its central London route in the busiest two peak hours.

The average delay for motorists travelling along the length of the north-south route will be 2 minutes 43 seconds in the busiest two peak hours. These estimates assume motor traffic will not fall in the next two years – it has fallen for most of the last decade.

Has this data helped reassure sceptics?

Not really – most interested parties say they don’t have a problem with the broad outline of the plans but they have still not seen enough detail to reassure them on how they will be implemented. Many have criticised the mayor’s office for rushing the process.

Many big companies have come out in support of the plans, including Deloitte, Euromoney, the Crown Estates, Balderton Capital, Canonical, Barratt London, UBM (formerly United Business Media) and JLL (formerly Jones Lang La Salle).

But there have been reports of an intense behind-the-scenes lobbying operation to destroy the plans, led by the Canary Wharf Group.

The City of London Corporation, which represents the Square Mile, says in public that it broadly backs the plans but has reservations about access for businesses – for deliveries, for example – and how the routes will work in the densely populated City where streets are used by large numbers of cyclists and pedestrians. The planned superhighways criss-cross the Square Mile along Upper Thames Street, Lower Thames Street and Farringdon Road.

Following the publication of estimates of how much drivers and pedestrians will be delayed on roads and at crossings once the scheme is in place, it says it still has not seen enough detailed data to reassure it that they are being implemented in the best possible way.

Michael Welbank, the corporation’s chairman of planning and transportation, says:

Of course we support the cycle superhighways but a lot of detailed work still needs to be done to ensure their success in practice. We have now got summary data but not the detailed data – which contains the local impact on surrounding streets. More thought also needs to be given to the working of the highways – both in the construction and the operation stages – and many local businesses would welcome clarity on issues such as deliveries, etc. These important proposals need to be got right – for the benefit of London and all who use the City.

Lucy Haynes, the CBI’s London director, echoes the desire for more information:

While we support moves to improve the safety of London’s cyclists, we need to see the full detail of the mayor’s proposals for dedicated cycle superhighways.

Almost half of London’s firms report that the capital’s roads are deteriorating, so we need to have all the facts about a possible impact on further congestion and journey times before we press ahead.

The CBI is discussing the business impact of the scheme with its members and says it will reply to the consultation in due course.

One independent transport consultant who has worked on previous London projects says he too is concerned that not enough information has been provided on the concrete steps to mitigate traffic delays that would need to be taken to make the plans work. “The devil is in the detail,” he says.

That the projected start date is just before the end of Johnson’s second term as mayor has fuelled criticisms that the proposals are being rushed through to form his legacy to London. Even some cycling lobby groups strongly in favour of the plans have been surprised at how fast the plans have been rushed through, he says.

On the positive side, concerns about access for businesses and deliveries could spur innovation in this field, and he believes the plans as they stand will not cause gridlock.

• Chris Boardman: Don’t let lobbyists destroy London’s cycle lane plans