As someone who lectures future doctors on health education, Trisha Revest knows more than most about the benefits of regular cycling. Yet even she worries about the short trip between her two east London workplaces.

The 59-year-old has to ride only one mile between Queen Mary University of London and the Royal London hospital, but the route takes her along the grandly named cycle superhighway 2 – in reality just a narrow, lorry-buzzed gully of blue paint on or near which three cyclists have died in little more than a week.

"Just look at it," Revest says, pointing to the construction trucks and buses rumbling past. "Where those cars are parked, you've got to swing right out into the traffic. I'm an experienced cyclist, but I don't like it. Pedestrians have their own space, cars have their own space. Cyclists need their own space, too."

Five cyclists have been killed on the capital's roads since 5 November, four struck or crushed by a lorry, bus or coach. While the rush of tragedies appears most probably an arbitrary statistical compression – in all, 13 cyclists have died in London in 2013, against 14 last year – it has focused attention on the efforts of London's mayor, Boris Johnson, to build a cycling infrastructure to match the city's growing platoon of bike users.

Members of the public at a shrine for the cyclist killed in Bow, east London. Photograph: James Perrin/Rex Features

The implications spread beyond London. National road casualty figures have shown a rising trend in deaths and serious injuries to cyclists, while driver casualties have dropped. London is seen as both a crucible and template for cycling in other cities, and the worry is that Johnson's initial schemes may have been found badly wanting.

While campaigners stress that overall, cycling remains many times more likely to lengthen your lifespan than to curtail it, some warn that the superhighway has proved a false start. Small sections snaking out from the centre are protected by kerbs, but for the most part they are demarcated only by blue paint, which, as a coroner examining an earlier death pointed out last month, could give cyclists a false sense of security.

Johnson and his new "cycling commissioner", the journalist Andrew Gilligan, announced last week that the superhighways would be improved, with far greater segregation. Some argue that the pace is too slow. "There needs to be a clear message from the top, from the mayor, that things need to change," said Rachel Aldred, an expert on cycling at Westminster University. "I don't think at the moment the message has gone out that you need to prioritise people over motor traffic flow. And so you get things like CS2 – a tiny line on a very busy, multi-lane road. From the very start, people were saying it was a problem. It wasn't changed, and people died."

Gilligan argues that people should recognise that the annual death rate in London is consistently decreasing: "It's understandable that this extraordinary and appalling series of deaths are going to obscure that fact, but it shouldn't happen in the long term. The danger I see from all this is firstly that cyclists get scared away from cycling, and also that it gives succour to those who argue that the mayor shouldn't encourage cycling because it's unsafe."

But he agrees that action is needed over CS2: "The cycle superhighways are mixed. Some are actually quite good and you never hear any complaints about them. But some are less good, and cycle superhighway 2 is the least good. I don't believe in just blue paint on superhighways, and we're going to change that."

Johnson and Gilligan's proposed model, outlined earlier this year, is a Dutch-style system of mainly segregated lanes and cycle-safe junctions. However, the Dutch warn that there is a long way to go. Weijer Losecaat Vermeer from the Dutch embassy admits that he has abandoned a traditional upright bike for a lightweight machine and specialist clothing. "If you come from the Netherlands and find yourself in a London traffic situation, the first thing you notice is that cyclists don't seem to be an equal road user," he said. "They don't seem to be thought of. The other thing is, in the Netherlands, every motorist is a cyclist as well. This thing you have in London of motorists versus cyclists doesn't exist."

One of the consequences of Johnson investing so much political capital – not to mention a planned £1bn – in cycling is that Westminster is taking notice. Both Labour and the Lib Dems have signed up to the ambitious recommendations of an all-party inquiry into cycling, which proposed consistent, coherent planning for bikes.

"Cycling has got to be normalised, rather than the sort of add-on and afterthought it's always been," said Mary Creagh, the shadow transport secretary. "Most of our roads were built and designed in the days when the primacy of the motor car was not challenged, and many of those 60s designs have failed the test of time."

Cities including Manchester and Edinburgh are already examining Johnson's Dutch-style plan. That made it all the more important to get things right, said Aldred: "They're looking at London very closely and seeing whether there will be improvements, or if we'll just carry on, which isn't an acceptable situation. Unlike some other places, London never had a particularly strong cycling tradition. It's always been a public transport city. And if London also becomes a cycling city, it'll be really inspiring."