I was deeply saddened and heartbroken to recently hear of the untimely passing of my former colleague and friend Ion O’Sullivan, who died after a short illness.

Ion worked in the transportation industry for 24 years, specialising in traffic signal engineering and traffic modelling. He displayed a genuine interest and passion for his profession throughout his career.

Ion began his career in the field in 1995 at Greater Manchester Urban Traffic Control Unit (GMUTC) before moving on to Transport for London (TfL) in 1998 where he worked until 2015. Ion spent his career there leading and implementing many key schemes, and he was heavily involved in the development of prototype tools and systems for improving the capability of London's traffic signal management system. Ion’s pioneering interest in traffic modelling at TfL included delivering their first in-house training course in the VISSIM microsimulation package and his involvement in the development and testing of the world’s first PC-based SCOOT UTC to VISSIM interface.

In 2015, Ion joined JMP Consultants (now part of SYSTRA), and it is here that I worked with him as his team leader. Ion spent around 2.5 years at JMP/SYSTRA as a Principal Transport Planner, and during this time he was involved in leading the development of traffic models for many schemes in London and throughout the UK, many of which have been implemented and are currently in operation on site. After leaving JMP/SYSTRA in 2018, he always stayed in touch. Later that year, he joined AECOM where he ended his career.

Ion was an individual of incredible character and personality. He will be remembered fondly for his intelligence, energy, humour and genuine interest in other people. Ion was the most positive and optimistic person I have ever met. He would always be smiling regardless of the situation and would always find a positive spin on any issue. He also never had anything negative to say about anyone or to anyone.

Throughout his time at JMP/SYSTRA, Ion was always very generous with his experience and wisdom, and a big part of his legacy in the industry will be the beneficial knowledge of traffic signals and junction modelling which he passed on to others including myself. This knowledge will continue to be implemented and passed on to others for many years to come.

Ion will be truly missed by myself and all others who worked with him.

In his memory, this tribute page has been set up. Please feel free to leave any memories of Ion here, and please also donate to support the excellent work of the Brain Tumour Charity.