The dangers faced daily by London cyclists hit the headlines last month when six were killed in 13 days, prompting protests and even calls for lorries to be banned from the streets during rush hour.

But away from the furore a number of British technology firms have been racing to perfect safety systems that it is hoped can save lives. Cycling deaths hit a five-year high in 2012, with 118 cyclists killed on British roads, and safety standards in the capital are coming under particular scrutiny.

Transport for London has commissioned tests of different warning systems based on radar and radio frequency ID – the technology used on the capital's Oyster cards – which could be used in London's 7,500 buses and countless lorries. Further tests on sensors and software systems will be carried out in the New Year on lorries used by firms constructing Crossrail and the EM Highways road maintenance company .

The TfL trials, which began in the summer, are attracting renewed interest following the outrage over last month's deaths. Three of the victims were killed by lorries, two by buses and another by a coach. In at least one of the accidents a cyclist turning left was struck down by a lorry going the same way.

The new technologies aim to correct this deadly blindspot, a major contributor to the toll of deaths and life-threatening injuries among cyclists in the capital. Trucks are involved in more than half of cycling deaths in London, according to the London Cycling Campaign, although they account for only 5% of traffic.

A Bristol-based firm, Fusion Processing, has designed a radar device fitted to the side of a vehicle which sends the driver a verbal warning, usually "cyclist left". Marketing director Jim Fleming said that in trials on a London bus, the Cycle Eye detected 93-97% of cyclists, without giving false alarms for objects such as benches and lampposts that would overload the driver. He says the finished product will detect 99% of cyclists, but that further winter testing is needed "to check the units survive bus washes, salt spray and the generally harsher weather".

A rival company, Safety Shield Systems, has opted for software connected to sensors and video cameras – the same technology first developed by the Israeli company Mobileye that can be used in self-driving cars. Safety Shield also tested radars, but found too many faults, said the company founder, Jon Guest. His Safety Shield issues two warnings: "If you are getting too close to a pedestrian or a driver, it just flashes. If it is looking like you are going to collide, it gives you a harsh beep and three seconds to brake." Guest's system is being trialled with lorries involved in Crossrail and at EM Highways.

Road safety campaigners have reserved judgment until the trials are complete. "If they are as good as claimed, the driver would have had a warning, but whether that warning would have come in time [for them to act] is hard to say," said Charlie Lloyd, campaigns officer at the London Cycle Campaign.

Lloyd is far less convinced by the third system under the microscope: a radio frequency ID system designed by Cycle Alert, akin to putting super-charged Oyster cards on bikes and lorries that "talk" to each other, with a dashboard device warning the driver when the cyclist is in their blind spot.

"We are not convinced by a system that requires one party to have one bit of technology and another party to have another," he says, arguing it is not feasible to fit RFID devices on all London bikes, including the countless ones languishing in sheds. "It just doesn't add up in safety theory."

He warns the system could even make roads more dangerous for cyclists by giving a false sense of security and making drivers over-reliant on a system only used by a minority of cyclists.

Peter Le Masurier, the founder of Cycle Alert, defends his RFID system as "an opportunity to educate cyclists and drivers". "That is fundamental and is something that the HGV industry and bus industry really likes about our product. It is the fact that the cyclist has to do something, has to take some responsibility."

TfL declined to say when it would reach a decision on the trials, but said that further innovations – including low-level signals and "Dutch-style roundabouts" which slow traffic and sometimes keep cyclists in separate lanes – would be tested next year.

Caroline Pidgeon, Liberal Democrat leader of the London Assembly, called on transport authorities to speed up road design improvements while they await the trial results. "Transport for London proudly stated that they had managed to install the new segregated bit of the Cycle Superhighway 2. It had taken them 18 months and they were trumpeting it as if it was really fast. Well 18 months is far too long for most Londoners."

Campaigners agree that London has "a legacy of 50 or 60 years of low-quality road design" to tackle. … The technology, the gizmos, are compensating for road design failure."

• This article was amended on 27 December 2013 to clarify that the number of cycling deaths hit a five-year high in 2012, with 118 recorded by the Department for Transport.