Road injury prevention measures seem to be effective, evidenced by a decrease in severe brain injury cases, says new research.

The number of people suffering severe traumatic brain injury (TBI) caused by road accidents has fallen in the nine years to the end of 2014, says new research.

But there's been an increase in severe TBI resulting from low falls, which occur more frequently in people aged over 65.

An analysis of incidents and causes of hospitalisations in Victoria from 2006-14 was carried out by Dr Ben Beck and colleagues from Monash University and the Emergency and Trauma Centre at the Alfred Hospital.

The incidence of severe TBI declined from 5 to 3.2 cases per 100,000 population per year, with most cases resulting from unintentional events.

In particular, the incidence of severe TBI in motor vehicle occupants declined 11 per cent per year, 12 per cent for cyclists and 5 per cent for pedestrians.

The decrease suggests that road injury prevention measures have been effective, the researchers wrote in the Medical Journal of Australia.

But severe TBI from low falls increased 4 per cent per year, meaning in recent years it was higher than for motor vehicle crashes.

Severe TBI resulting from intentional events such as violence and self-harm was 0.60 cases per 100,000 population per year, and had declined by 5 per cent per year.

"Ongoing efforts to reduce road trauma, interpersonal violence and intentional self-harm injury are warranted, while increased efforts to reduce fall-related injuries and injuries to vulnerable road users are needed," they said.