(1) could well follow a Poisson distribution so long as the road is not used as a rat run by commuters in the rush hour.
(2) will be a Poisson distribution since particles are emitted from a radioactive substance completely randomly and at a constant rate.
(3) is unlikely to have a Poisson distribution – people will probably leave in groups (so events will not occur singly). Also more people will leave in the run up to closing time, so the rate will not be constant.
(4) could be a Poisson distribution as long as the sampling process is carried out carefully in one area.
(5) could be a Poisson distribution – there is a possibility that errors might not occur independently, as some parts of the novel may have been typed when the author was tired and therefore more prone to making mistakes.
(6) is unlikely to be Poisson – the events are unlikely to be independent. If one accident has occurred, another is more likely than usual (perhaps because of drivers looking at the accident scene or simply because driving conditions are poor).