On their own, mostly not, or not for long. In a controlled fleet trial, in-cab warning lights alone made no significant difference against a control group. The same lights with a supervisor coaching the drivers cut risky driving significantly more than the lights alone (Bell and colleagues, Journal of Safety Research, 2017). TRL's review for HSE and the Department for Transport put it plainly: "Organisations should not rely solely on in-vehicle feedback."
What the research shows
The trial ran the same drivers through a period of warning lights in the cab and a period of lights plus coaching from a supervisor using recordings of their driving, measured against a control group. "Lights-only feedback was not found to be significantly different than the control group's decline from baseline", while risky driving fell significantly more once coaching was added.
TRL's 2020 review of vehicle safety technology was written to help update HSE's guidance on driving at work. It reached the same view: "feedback which involves coaching (goal setting and feedback) is more effective than in-vehicle alerts alone."
The effect also fades without follow-up. Dr Lisa Dorn, then at Cranfield University, told fleet managers in 2018 that "If fleets do not keep messages going and reminding drivers of their responsibilities... then very soon behaviour drifts back to before interventions were introduced", adding that "Having a conversation with drivers once a week is very beneficial" (reported by Fleet News).
Why the conversation doesn't happen
Most fleets know this already. The difficulty is time. The driver manager plans to speak to a driver on Friday morning, then a breakdown, a customer complaint or a roadside stop takes the morning. The chat slips a fortnight. Most systems stop at the data, so the driver manager still has to contact each driver by hand.
What a useful conversation looks like
- Early, while the change is small, rather than after an incident
- About a pattern, such as more harsh braking this week than last, not one event
- Welfare first, because a change in someone's driving can mean something is going on outside work
- A well done when it's earned, since drivers who only hear about the bad weeks stop listening
- Straight when a pattern carries on, with the door left open to talk
Where SHIELD fits
SHIELD's Driver Influence looks across every connected system to pick out drivers whose driving is starting to change. It checks in with them on the SHIELD app in plain English, welfare first, with a well done when they improve. A positive one reads like this: "You're running 94 to 96% better than the fleet average on speeding. That's solid consistency over the last couple of checks. Keep that up." Drivers rate each message they get. The office sees every check-in sent and how the driver rated it, so a manager's own time goes on the drivers who need a person.
Read more
Sources: Bell, J. L., Taylor, M. A., Chen, G. X., Kirk, R. D. and Leatherman, E. R., "Evaluation of an in-vehicle monitoring system (IVMS) to reduce risky driving behaviors in commercial drivers: Comparison of in-cab warning lights and supervisory coaching with videos of driving behavior", Journal of Safety Research 60, 2017; TRL, PPR968, "Assisting the update of INDG382: vehicle technologies", July 2020, for HSE and DfT; Fleet News, "ACFO seminar: telematics very effective in changing driver behaviour", 22 May 2018.