This is from the old RIDDOR guidance L73 ( it is sort of in the latest HSE document indg453 but less detailed). I have highlighted in red text
Enjoy
Chris
Accidents caused by moving vehicles on the road
95 Regulations 3 and 4 do not apply to accidents involving vehicles moving on
public roads unless they involve or are connected with:
(a) exposure to any substance being conveyed by road;
(b) vehicle loading and unloading activities such as those performed by refuse
collectors, brewery delivery workers, furniture removers etc;
(c) the specified construction, demolition, alteration, repair or maintenance
activities on or alongside public roads; or
(d) an accident involving a train where a person is killed or injured.
96 In the case of (a) to (c) in paragraph 95 regulations 3 and 4 apply whether the
injured person is engaged in one of the listed activities or whether they are injured
as a result of the work of someone else who is engaged in such activities. For
example, the following would be reportable under regulation 3:
(a) an employee of a building materials supplier dies as a result of being struck by
a passing car while unloading bricks from a lorry;
(b) a motorist driving past a building site alongside the road is injured by falling
scaffolding from the site. This would also apply if the motorist was an
employee and suffered a ‘major’ injury;
(c) the driver of a road tanker suffers gassing and acute illness as a result of
exposure to a toxic substance spilled from the tanker or, as a result of the
same spillage, a member of the public is taken to hospital for treatment as a
result of exposure to the substance;
(d) an employee painting road markings is hit by a car and does not suffer a
major injury as a result, but is unable to do the full range of their normal duties
for four days.
97 Dangerous occurrences on public highways are covered by the Regulations,
and so are accidents and dangerous occurrences on private roads (ie those not
covered by the Road Traffic Act 1988