What is the toughest part about traffic accidents investigation?

The toughest job while investigating the traffic accident are to collect the physical evidence, to maintain status co till the investigation team arrived, pressure of traffic crowd to clear the road and also it will help to avoid recurrence with consideration to collect the maximum evidences either taking the snaps or sketches

The toughest part in traffic accidents investigation are :
1- Crowd of watchers , a lot of intruders .
2- Intrusion or tamper the evidences .