Background In 2013 the London Mayor committed to increasing cycling levels by 400% (from 2001) by 2026. Although the numbers of deaths per year are relatively low cycling in London has become highly politicised with significant media focus on every cycle death in the capital. This study was commissioned by Transport for London to explore contributory factors to cyclist deaths and implications for interventions.

Methods This study involved an in-depth case review of 53 pedal cycle fatalities in London between 2007–2011. Police fatal reports were used in the analysis. The method involved application of a Haddon matrix approach to data analysis and a case by case review by a multidisciplinary team to explore the multifactorial nature of contributory factors from a safe systems perspective.

Results Over half the crashes involved a truck (>3.5 tonnes) as the primary collision partner, most happened during daylight and the commute period, on low speed (30 mph) urban roads and at a junction, particularly at a complex junction. A notable finding was the involvement of trucks in fatalities, particularly for female cyclists, where the truck was turning left. For these crashes contributory factors were identified as poor visibility of the cyclist to the truck driver related to cab design and lack of mirrors, poor positioning by the cyclist and infrastructure issues such as lane narrowing creating a conflict point between cyclist and trucks.

Conclusions Potential countermeasures to mitigate risks for cyclists include the design of trucks to create greater visibility of vulnerable road users, training of both drivers and cyclists to raise awareness of visibility and designing infrastructure and managing traffic to reduce the opportunities of conflicts arising in the first place. Few well designed intervention studies were identified. The overrepresentation of female cyclists in collisions with left turning trucks is an issue that warrants further investigation.