Is this legitimate? RTCs haven't been called RTAs for a long long time.
They are by me, and I think it probably is 'legitimate' in the context concerned.
To achieve (national and internal) consistency, comparability and 'analysability', most official statistics classify diseases (and causes of injury/death) using the WHO's International Classification of Diseases, the current version of which is "ICD-10", which I use all the time. In context, virtually all the the relevant classifications are all within the section "Transport Accidents (V01-V99)", and each of those 99 classifications (and all the hrirsrchy of subdivisions thereof) include the word "accident". That word is used in its everyday sense, to indicate a lack of 'intent'. For the very few cases in which 'intent' is known or may be involved, there are other classifications (with subdivisions), which do not involve the word 'Accident', such as:
Y03 Assault by crashing of motor vehicle
Y32 Crashing of motor vehicle, undetermined intent
As a result, I often find myself writing about 'RTAs', rather than 'RTCs'. In fact, strictly speaking, whilst the vast majority of incidents on the roads which result injury or death do involve 'collisions', a few do not, at least in terms of the normal understanding of the word 'collision' - for example, if a motorcyclist comes of his/her bike (without the bike striking any other vehicle or person), there is not necessarily any 'collision', other than the person's body contacting the ground.
Bernard may be right in suggesting that the change from RTA to RTC was an attempt to remove any implication that no 'intent' was involved, which might have legal implications. However, I'm not sure that would really have been necessary, since there are surely only a tiny number of cases in which there was 'intent' to cause a traumatic incident - and, in any event, lack of 'intent' does not preclude negligent behaviour. One can, for example, be guilty of causing death or serious injury by dangerous driving even if there is not the slightest suggestion that there was any 'intent' to cause harm.
Kind Regards, John