Intelligent speed assistance (ISA) is an in-vehicle technology that supports drivers to stay within the limit. To promote ISA use, we have been conducting research to develop an educational package based on what drivers think about ISA.

One of our key findings was that UK drivers are often unfamiliar with ISA, so, first, I’ll explain what ISA does!

ISA technology comes in two flavours:

  • Advisory ISA: When the speed limit is exceeded, the system provides an audio or visual warning so that the driver can take remedial action.
  • Intervening ISA: When the speed limit is exceeded, the vehicle reduces power, gently returning it to the speed limit. Drivers can override the system if they feel that is appropriate.

In this article, I focus on intervening ISA as the evidence indicates it can be more effective than advisory ISA in reducing crash risk. Many manufacturers are fitting intervening ISA to their vehicles as standard or as an optional extra, and it is being adopted by large-scale fleets such as Transport for London.

As ISA becomes more widely available, it can reduce crashes but only if drivers voluntarily use it. The Road Safety Trust awarded us grant funding to construct an educational package about the benefits of ISA. (Full reports on this, and all our work in this project, are publicly available, as listed in the reference section.) As ISA is not yet common on UK roads, we set out to develop a leaflet and linked video animation that drivers could access at the point of purchasing an ISA-enabled vehicle.

We based our educational package on the results of a survey of several hundred drivers that identified the most influential opinions about ISA. In a subsequent study involving more than 1,000 drivers, we found that engaging with our materials strengthened intentions to use ISA. We would be delighted for anyone to either use our materials (they are freely available) or to design their own materials focusing on the issues that we have highlighted.

What are the key issues relevant to ISA use?

Key positive perceptions regarding ISA that were identified included that it could help avoid speeding penalties and fines and “give me peace of mind”, as well as reduce one’s crash risk. Therefore, these are all important aspects of ISA to highlight in educational materials.

Concerns about ISA were also raised. Addressing these concerns in educational materials is important to reduce barriers to using the technology. One common concern was that the vehicle might slow down suddenly. This is often related to a belief that ISA is linked to the brakes. Educational materials can address this by explaining how ISA works: that the vehicle’s power is cut if the vehicle exceeds the speed limit, gradually slowing the vehicle - the brakes are not involved.

Addressing concerns about ISA is important to reduce barriers to using the technology. One common belief is that ISA is linked to the brakes. Educational materials can address this by explaining how ISA works: the vehicle’s power is cut if the vehicle exceeds the speed limit, gradually slowing the vehicle - the brakes are not involved.

Other concerns included that ISA may be restrictive or reduce driver control and might get the speed limit wrong on occasions. There are often discussions over whether there may be situations where speeding might be the safest course of action. To deal with these situations ISA has an override option. If there are circumstances where drivers feel that speeding up momentarily is the safest option, then they can use the override, so they remain in full control of the vehicle. The override option is therefore an important ISA feature to emphasise in educational materials to anticipate these concerns.

The road ahead with ISA

Our work with drivers who have intervening ISA indicates that the majority find it useful. We have recently collected data (as yet unpublished) which shows that 90% of drivers who have ISA have driven with it enabled for some time in the previous week. Our colleague at Transport Research Laboratory, David Hynd, wrote an excellent blog describing his own positive experiences using ISA.

As ISA technology becomes more common, making vehicles safer, a key limiting factor for the potential of ISA to reduce road crashes will be the extent to which drivers choose to use it. If you have the opportunity to promote ISA in your work, then feel free to use our materials and research findings to encourage drivers to give ISA a try.

Richard Rowe, Professor of Psychology at the University of Sheffield, wrote this blog for Road Safety Week 2025. Click here to find out more about Road Safety Week.

References Down arrow icon to open accordion
  • Day, M., Norman, P., Poulter, D., Özkan, Ö., & Rowe, R. (2023). The adoption and application of Intelligent Speed Assistance by private motorists: User and non-user perspectives. Transportation Research Part F: Traffic Psychology and Behaviour, 99, 262-273. https://doi.org/https://doi.org/10.1016/j.trf.2023.10.016
  • Day, M., Norman, P., Poulter, D., Özkan, Ö., & Rowe, R. (2024). Stakeholder perspectives on the adoption and application of Intelligent Speed Assistance in UK vehicles. Journal of Transport & Health, 38, 101868. https://doi.org/https://doi.org/10.1016/j.jth.2024.101868
  • Özkan, Ö., Norman, P., Rowe, R., Day, M., & Poulter, D. (2024). Predicting drivers’ intentions to voluntarily use intelligent speed assistance systems: An application of the theory of planned behaviour. Transportation Research Part F: Traffic Psychology and Behaviour, 104, 532-543. https://doi.org/https://doi.org/10.1016/j.trf.2024.06.003
  • Özkan, Ö., Rowe, R., Norman, P., Day, M., & Poulter, D. (2025). Increasing drivers’ intentions to use Intelligent speed Assistance: A randomised controlled trial of a theory of planned behaviour-based intervention. Transportation Research Part F: Traffic Psychology and Behaviour, 111, 238-249. https://doi.org/https://doi.org/10.1016/j.trf.2025.03.003
  • Rowe, R., Norman, P., Day, M., Poulter, D., & Ozkan, O. (2024). Promoting Intelligent Speed Assistance to Reduce UK Road Traffic Crashes. Road Safety Trust. https://static1.squarespace.com/static/61d570b3a2957b5f755587d2/t/6720dd28dec93d5c1b8bced4/1730207018336/Sheffield+Uni+ISA+Final+Report.pdf

Richard Rowe, University of Sheffield

Richard Rowe is Professor of Psychology at the University of Sheffield. His research addresses factors underlying risky and antisocial behaviours in young people and the development of interventions to reduce these problematic behaviours. Major focusses have been on disruptive behaviours in children and adolescents, and risky driving in young motorists.